I agree with hubbard - the ground is pretty uneven and the trail is more of an easy hike (for a fully mobile person) than a stroll. It sounds like your mom would have difficulty. The path is not paved. It was sandy and rocky, big steps over or on to boulders, that kind of thing. Definitely not a stroller friendly path.
Going it alone was very easy. You might investigate Spring Bay Beach. We didn't get there but I read it is right up the coast from Baths, has boulders as well but no facilities. You could take a taxi there so your mom could get similar scenery without the strenuous walk.
I don't think I ever saw a line in Sweet on You. We walked by there a lot because our room was on deck 10 aft. We didn't even try it because we were always so full from the regular meals! I don't think you'll have trouble finding a good time to pop in.