Keeping a GP 3.1L in good shape...

Okay, I have an '02 GP SE with the 3.1L and I put a lot of miles on this car. Unavoidable and not going to change, so taking the approach of trying to do everything possible to keep all parts in good shape and follow a thorough maintenance schedule. The car has 64k on it, in two and a half years - that's about 2100 miles a month, and I do not forsee that average going down much in the future. I occasionally push the engine, but for the most part drive reasonably, at least reasonably enough to manage 28-29mpg. I already keep up 3500 mile oil changes, using Mobil 1 full syn 5w-30. At 30k and 60k I changed tranny fluid and filter using Mobil 1 full syn ATF. Changed spark plugs, with platinum fac. replacements, at 50k. Drained radiator and cleaned basin and radiator system out at 30k and 60k. I don't rotate tires as often as should - probably do it about every 15k. Have not changed fuel filter, need to I know. Took apart and cleaned throttle body and filter box at 30k and 60k, soon to replace with an do-it-myself FWI unless someone has any negative feedback about the FWI setup? Does anyone have info on where the PCV is on the 3.1L? Everything I've seen states specifically for the 3.8 and 3.8 SC.
I Take the car for a "check-up" at a local shop that does a 60-something-point check for free when getting a rotation and they say I keep it up well. But please if anybody can suggest any maintenance I'm missing or just overall suggestions to keep this car running for the next 60k pass on the info, it's much appreciated!