Drive or Overdrive in a 700r4

[Coach]

OK guys, this is probably a stupid question but I'm going to ask it anyway. Just picked up my truck last night, had the tranny rebuilt since it never had Overdrive (had been driving it like a 3 speed). Should I leave it in D (Drive) all the time around town and only shift into OD (Overdrive) when on the freeway, or should I drive around all the time in OD. I'm thinking D all the time then shift to OD on the freeway, but wanted some advice from guys who have had 700r4 in the past. Thanks for any advice.