Once you get up high enough I don't think you will ever be wanting for things to do on that map! LOL
Between the Car sales, Crate Drops, Armored Truck heists, and all the new missions opening up, it becomes a continual thing LOL. Log in for 3 minutes to sell a car and wind up in an hour long adventure LOL.
(plus please don't forget player created missions and heists are soon to come, as well as additional map locations Rockstar is going to add, this is just a beginning)
"One more crate....but that's it I swear!"