So for some reason, I can't remember now, but my disc of all of my zipped up Sierra games was in my disc drive so I decided to go ahead and look through some of the games that are on it.
I just finished playing Ecoquest I with 685 of 725 points. For some reason I never actually played too much of this game before. I remember I would always got lost in the kelp forest on the way to the underwater city. This time however I managed to make it straight there. After that the game pretty much played itself, none of the puzzles were overly challenging. There was one item that took me a while to find, and is the only reason I didn't beat this game in one sitting.
It's definately not one of the first games I would suggest, but if you haven't played it in a while it's not a total waste and it should go relatively quickly.