Which to choose for a 4-5 day

[NOSaints1]

Want to take my parents on a cruise, there in their mid 60s, my DW and I've gone on 3 Carnival and one upcoming RC cruise. Theve never been on a cruise and always helped us out, we don't want to spend a lot as there's four of us, and were also in Canada so all rates would have to be converted and would be traveling from Ontario, want a good ship, good food, enough to do but my Dad has trouble walking, good ports. Looking at 2017 as our RC is in Oct 2016 out of San Juan.