The AA is a great institution but can be a hit or miss. Personally it is not worthwhile for me. I just call the nearest carrier lorry if the car is unfixable. However it depends on the individual. I know they helped out my mother a few times in the 90s when she got stranded with her behemoth Patrol with a flat. Their Club house near the Ramada offers cheap booze and food, so there's that.
Companies do fully insure classic cars. Speak to an agent.
There are a few dedicated classic car garages, but not worthwhile for a Lancer IMO. Best to give it to a trusty local mechanic and to study the car yourself. Educate yourself on the basics like how the carbs work, ignition timing etc.
Anything over 25 years is bound to give you trouble. That's part of the deal. The best you can do is not to take short cuts mechanically when restoring. Be warned, you will come across some shit cars on your collecting journey, that breakdown constantly no matter how much you spend. I am not superstitious at all ,but I nearly burned down an RX7 FC because that f*ckr of a car brokedown all the time. Then the FD Efini I had with more or less the same Wankel was just bulletproof. So yes, cars do have personalities.