i have researched all this as well as i have an aod as well. there's a 2000 stall you can get for around 160, and a 23 or 2400 stall for around 275, as long as it's a lock up type converter you should be ok, as far as cruising on the freway in od, it will be locked up and not slipping.
as far as power/rebuilding from what i have researched it depends on what you wanna pay. you can sppend 2 grand on a high dollar lenteck and it' will handle anything a 302 will throw at it. basically, you want a trans go shift kit or high performance valve body, heavy duty clutches and bands, an external cooler, and i believe there's a couple other mods a good tranny shop can do to it and it should be good to go. probably cost about a grand if you took it somewhere and had them do it all........labors the killer there....