1

Lots of questions there but to get the answers underway i would say your budget is good, your route seems good for a three month trip, if you fall short of your destination it wont matter anyway just get a bus or train for your flight home. As for food i would say eat what you feel like eating but try to in the main to have a healthy diet.

2

Some comments, based on my two tours in France (blog here).
Try to stay away from major towns and major roads between them. Secondary roads ("D" roads) that seem to wind away from major towns are the best. Your budget seems reasonable, if you camp most of the time. It's not difficult to find a wild camping space - there are lot of woods. Some places have municipal camping grounds, which are very cheap or even free. Private campings are more expensive. There are also "Gite d'etape", a king of cheap hostels, on some hiking destinations. French passes are fantasic. Cyclists are respected there. If you like climbing, then I'd go over as many as possible. Route de Grand Alpes connects some legendary climbs, but it's very popular with motorists too, particulary in August. You can also choose different and more peaceful route. I'd choose the itinerary using Googe maps. Water can be taken from town fountains, graveyards, official campings and from restaurants (not from petrol stations). Food: eat what you like, cycling will keep you healthy.

3

When do you leave? Might be a hot arriving in Greece in the height of Summer, cycling in the Peloponnese is brilliant however, but having been there a few times I wouldn't want to be there before September. Don't know about Italy but free camping in France is possible iv'e done it quite a few times, but the campsites are pretty good and relatively cheap, so don't try to free camp too often - in the middle of Summer you'll be grateful for a shower after cycling all day. It depends also how much you want to cycle over the alps, it will slow you down quite a bit carrying a fully laden bike with a tent. Having cycled in France (most years for the past twenty) I would suggest going through the massif central then to Provence, from Avignon head to Nice via the gorge of Verdun. At Nice take a ferry to Corsica then to Livorno from where you can cycle across Tuscany and from there to the ferry to Greece. I don't remember the Corsica ferry being at all expensive. You ask if it is practical/affordable to got to Corsica. On the contrary I would say that it is much more desirable; you will avoid some busy roads, will have less ground to travel by missing out a big chunk of northern Italy and get to cycle round Corsica - which is great

That seems like loads of money per month, cycle camping, I tend to spend less money than at home - I can do it very cheaply. I assume that you will be cooking your own food. What kind of fuel stove do you have. I use a trangia. Meths in France is really cheap.
Costs £5 - £6 per campsite, £5 - 10 for food and wine, which is what 20 euros per day. If my memory is correct I spend £200-300 per 2 week holiday - but people do say I am a bit tight.

Few other points. I cycled on Sardinia for a day only, so can't say too much, but the benefit of going back to livorno rather than Civitavehcia is that is then easier to cycle through Tuscany if you want. Cycling in the Alps is hard - as you can imagine - certainly don't do it unless you are well balanced, 2 panniers front and back (4 small panniers - stops you taking too much stuff and your balance is better) with the tent on the bag is best, with suitably low gears and using a proper Touring bike (at a push you can use a converted mountain bike I guess - but I use a Ridgeback tourer). If you have to get out of the saddle because it is steep and are top heavy (everything piled on the back) that is no fun at all. Outside the Alps you are still of course going to encounter some really mountainous terrain; Corsica and Tuscany are hilly, so also is Greece - really mountainous.
Personally I would leave the Alps for another time you'll be cycling over plenty of hills- and head for Provence and Nice (and Corsica).

4

Thanks to you all for taking the time to respond to my questions, especially 'gmuir': lots of practical advice there. I was planning on bringing 4 panniers for balance (I also have a Ridgeback touring bike) and trying to travel as light as possible. I was planning to cook my food or eat cheap out of supermarkets etc but I just have a basic Campinggaz stove so i wont be whipping up anything fancy. I like your idea about avoiding the Alps via the south of France and Corsica, I realise it will be hard crossing the Alps on a fully loaded bike, but I do sort of have my heart set on doing it anyway, I've never been there before whereas I've been to the south of France a couple of times. Hopefully I'll be considerably fitter by the time I hit the mountains. As for Italy/Greece/Corsica/Sardinia I did have my heart set on those destinations too but it looks like time and money constraints may put those ambitions on ice for a while, I may only have a week or 2 in northern Italy before heading home. Oh well there is always next year.
I'll be sure to let you all know how I get on if any of you will still be interested. Hope to head off in early May, probably get home mid June.
Thanks again!