As one of those riders "kitted out" in local racing club kit, it's kind of annoying when guys sit on my wheel and "race" me. It's polite to come up and say hi. Then if they can't ride side by side and talk at the speed I'm going, I'm ok with them sitting in. Or we can trade pulls. When I'm by myself I am usually doing an endurance (or recovery) ride, so keeping up with me is not that big a deal (not that it ever is on flat ground).
As far as motivation goes, I can't think of anything more soul destroying than doing a lot of laps of the same course. Its like bringing the boredom of trainer riding outdoors. You have a lot of nice roads around LA, go ride them. The best way to get used to the heat is to turn down your home AC, turn off your car AC, and go ride in the heat. You'll get acclimated after a few weeks of exposure.