1

It is possible to do the physical journey in 3 months, but to do the journey and actually see and experience the countries you are passing through, I don't think you timeframe is good.

Either shorten the journey or add a few extra months, would be my suggestion.

2

Hi lasaki86!

Welcome to TT!

It all depends on what do you want to make. If you only want to travel overland from Mexico DF to Panama and from Quito or Lima to Rio de Janeiro, it's possible to make it in the timeframe you quote. If you want to visit all the countries along your route, well, you could spend all your time in Brazil and you wouldn't be able to see it all... If you want to visit only some locations at each of the countries along your route, it could be a good idea to open new threads (one in the Central America branch for the leg from Mexito to Panama and another one in the South America branch for the leg from Quito -or Lima- to Rio de Janeiro) asking for the time you would need to visit them (or, even better, list them and the time you plan to be at each of them and ask for opinions about it).