Not sure there's an "easy" solution to remote start. Kits are cheap from directed electronics -- even good ones, but the laborious process of install, and the expertise/constitution needed, is extensive to avoid issues. So I've heard...
If you aren't good with wiring, this isn't for you because its a lot of wiring. There is no easy remote start for a 4th gen 4runner. Directed remote starts are the best IMO.