Hi, royal99, and a very warm welcome to the DIS.
All you need to tell the guard is that you are visiting/picking up/dropping off your relatives who are staying there. We've done this at various onsite hotels. There's no need to make up a story.
Having a few drinks at the bar is not only possible, it's positively encouraged, so have no fears there.
As far as the pools are concerned, I'll repeat my earlier observation that, if you have no conscience and balls of brass, you probably wouldn't be challenged (other than at those specifically singled out). I'm certainly not condoning it and neither would I contemplate doing it, I'm just stating the facts as I see them. Having said that, I might consider spending spending time at a pool with friends or family if they were staying there.
Disney transportation is free to all, whether staying onsite or off, so there is no requirement to show anything. As discussed ad infinitum in this thread, other than temporary permits, parking at resorts is reserved for guests staying there. I'll undoubtedly get flamed for this (I have thick skin

), but in your circumstances I'd have no qualms in leaving my car at Port Orleans on the odd occasion to travel with my family.