Your question as to what is a good score can really only be answered he individual golfer. First, you are encouraged to tee off from a tee box that is compatible with your ability. Second, you are playing with course rules that are very liberal but designed to keep the game moving. Ball drops that are conveniently placed close to the greens, not in accordance with normal golf rules. Limits to the amount of shots allowed per hole. And then there are your own rules, do overs, give-me putts, penalties for out of bounds, etc. Whatever rules you pick and stay with can establish your norm. If you have a round that is better than your norm, great. Over time you may decide to move to a closer Tee box. New norm.

The golf course giveth and the golf course taketh. An average player can hope to leave with the same, or more, golf balls than he started with.

Scoring
 

Been back at golf about a year now and seem to be settling back into about the same level of play that I had a few decades ago prior to having the short game yips take over and run me out of the game.

I'm about to conclude that I tend to average about the same number of strokes over par (rarely at or even under) for nine holes on an executive course as I did when playing on "championship" courses with a similarly wide range between the "good" days and the "bad" days. I would *not* be making those same scores now from the same tees that I played back in the olden days. Time wounds all heels.

Good score is subjective. A really good golfer can shoot 1-3 over par and that might be a good score for that person. To an average golfer 1 over par for each hole might be good, Set your own goals and try to play to that level or better.

I feel like with the Executives in TV it's starting to look like breaking 40 is sort of like breaking 100 and breaking 35 is like breaking 90. (roughly)

Disgust levels
 

That 35 and 90 sounds like the right ballpark to me, too, thinking of it in terms of my level of disgust for the failure of either occurrence. :-)

A good score is better than your average, a great score is your new all time low.

This has already occurred. For the life of me, I wonder how this will work.