Is it feasible to drive from the USA to the southern tip of South America?

Sounds fine to me. Note that the southern tip of South America is not actually accessible by car, but you can get pretty far (either Punta Arenas, or catch a ferry onto Tierra del Fuego and drive to Ushuaia). Now whether your car can make the trip, I don't know, but you sound like you know what you're doing with the car.

All I can really tell you is that, in general, it is doable by car. There are acceptable (tarred) roads all the way from Colombia to Chile/Argentina, and there are various different routes you can take (with the main choice being where you cross the Andes, or even whether you criss-cross them multiple times). Note that you will have to pick your timing and plan your trip well. Some of the passes, particularly in the south, shut due to snow in the winter, and if you venture into the Amazon basin, there are roads that cannot be taken in the wet season.

EDIT: there are some obvious concerns with regards to road safety. You probably know already that what counts as an acceptable tarred road in South America (general, with regional variations) is not necessarily OK by US or European standards. Expect pot holes, narrow hairpin curves (which you contest with trucks), and at times crazy traffic. If talking about safety, I would worry more about the road and traffic conditions than carjacking, which while a serious issue, is quite unlikely.

Sounds fine to me. Note that the southern tip of South America is not actually accessible by car, but you can get pretty far (either Punta Arenas, or catch a ferry onto Tierra del Fuego and drive to Ushuaia). Now whether your car can make the trip, I don't know, but you sound like you know what you're doing with the car.

All I can really tell you is that, in general, it is doable by car. There are acceptable (tarred) roads all the way from Colombia to Chile/Argentina, and there are various different routes you can take (with the main choice being where you cross the Andes, or even whether you criss-cross them multiple times). Note that you will have to pick your timing and plan your trip well. Some of the passes, particularly in the south, shut due to snow in the winter, and if you venture into the Amazon basin, there are roads that cannot be taken in the wet season.

EDIT: there are some obvious concerns with regards to road safety. You probably know already that what counts as an acceptable tarred road in South America (general, with regional variations) is not necessarily OK by US or European standards. Expect pot holes, narrow hairpin curves (which you contest with trucks), and at times crazy traffic. If talking about safety, I would worry more about the road and traffic conditions than carjacking, which while a serious issue, is quite unlikely.

This is great info, thank you! Punta Arenas is my mental "ending point".

Driving is a passion, and I've spent many years racing fast cars and driving in very dangerous conditions, including lots of regular driving in snow in the northeast USA. I've also spent many years on motorcycles and because of this I have learned to be a very alert driver. In the car I will bring a pretty thorough tool kit, a spare tire, fix a flat, replacement serpentine belt, spark plugs, coolant, oil, transmission & brake fluids, extra headlight bulbs, mini air compressor, jack and stand, and some blankets, a pillow, and a ton of trail mix :)

Thanks for the heads up on the mountain pass and rainy seasons closings! I just drove quite a bit in Mexico and while there certainly were nice stretches were I could do 100mph, there were definitely plenty of "oh shit" moments when there were holes the size of the car :)

I'd suggest getting some of that muffler tape (you might bottom out or scrape it and easier to use a cheapie quick solution that let it get worse and have to pay for metal work) and some of whatever you could use for your oil pan...
I have an old VW (and learned to drive in a 56 sunroof) so I've been around old VW drivers and heard of their 'repair kits'....I've not used either but
when you hear tales of long trips and almost-disaster-scenarios (sometimes expanded on at great length, sitting around a campfire sort of story) you remember the 'fixes'.
Make sure you have a notebook and keep track of your 'fixes'!

Hah, I have that mental notebook, but maybe I should write some of them down before I forget them. Last year I drove a 20 year old race car across the country by myself, and I shattered a serpentine belt pulley in the middle of the desert at night. Teenagers helped me find parts and gave me a shot of whiskey for the road after we got the car running hours later. I took off from arizona into new mexico in the early a.m. hours and drove every waking hour until I hit the east coast. I lost a little hearing from that..

As far as the car goes, perhaps I should think about getting something with more ground clearance. Are Subaru parts readily available in central and south america? I could trade my accord in for something more practical, but i want to make sure i'm not stranded without parts access.

Are Subaru parts readily available in central and south america? I could trade my accord in for something more practical, but i want to make sure i'm not stranded without parts access.

Not really and therein lies the rub. Neither Subaru or Honda are particularly popular makes of car and parts are harder to source and more expensive. In Colombia, the sedan market is dominated by Chevrolet and Korean sh*#boxes. In Brazil the dominant brands are Ford, VW, GM/Chevrolet, Fiat and Renault, in no particular order. There's also Effa, from Uruguay, short for 'effan' awful motor vehicle'. Toyotas can be fond across the continent.

Go with a Fraud/Ford, Chevy or a Toyota if you want parts and a vehicle you can source locally in the US would be my best guess.

I understand you want to make that trip driving your own car, but, possibly you could consider the economical part of selfdrive vs. busses, or all the fuel, spare parts, etc vs. price of bus ticket.
Would that be an altivernative for you - drive to Panama, park (or sell) the car there, and continue from Colombia on busses?

Are Subaru parts readily available in central and south america? I could trade my accord in for something more practical, but i want to make sure i'm not stranded without parts access.

Not really and therein lies the rub. Neither Subaru or Honda are particularly popular makes of car and parts are harder to source and more expensive. In Colombia, the sedan market is dominated by Chevrolet and Korean sh*#boxes. In Brazil the dominant brands are Ford, VW, GM/Chevrolet, Fiat and Renault, in no particular order. There's also Effa, from Uruguay, short for 'effan' awful motor vehicle'. Toyotas can be fond across the continent.

Go with a Fraud/Ford, Chevy or a Toyota if you want parts and a vehicle you can source locally in the US would be my best guess.

So maybe a Toyota Tacoma would be a good combination of reliable, available parts, ride height.. i guess not quite good fuel economy.. but i can't think of another vehicle that can do all the others any better..

I understand you want to make that trip driving your own car, but, possibly you could consider the economical part of selfdrive vs. busses, or all the fuel, spare parts, etc vs. price of bus ticket.
Would that be an altivernative for you - drive to Panama, park (or sell) the car there, and continue from Colombia on busses?

I like being on the road, behind the wheel, so while I certainly wouldn't object to going via public transportation, the appeal to me is in the drive and the freedom. I wouldn't mind leaving a crappy car in panama for a few months, but if it was decent, like more than $5k, I would probably be nervous it wouldn't be there when i got back lol.

When I was thinking of doing this in my 10 year old honda accord, I didn't really care about theft, but if I was to buy a $15k toyota tacoma, id be a little worried about it disappearing. Is there any kind of auto insurance that would cover me in multiple countries? I checked and my company won't even cover me in mexico, let alone a trip through 15 countries..