Things we have done and enjoyed: Wine tasting (we visited a vineyard with an excursion, and we visited various wineshops on our own), Horse back riding on the beach, Visited the La Bufadura (really good tacos there 1st stall). But our favorite thing to do is walk around and shop.
Yes it's walkable and there is a sideway (elevated in some parts). Some might find the walk itself to the lighthouse steep. But getting there isn't difficult or dangerous.
There are also tons of shops in Cabo, PV, and Mazatlan where she can buy one. There are also several malls between Los Banos and Long Beach (I'm assuming your driving, but i've seen swimsuits for sale at LAX before).
Yeah, eating in the MDR is slow (on RCCL too). Plus, my wife is on that intermitted fasting, so the hours don't match up well for her. We generally have a large lunch and something light later on.