Tenders are little boats, used to ferry passengers from ship to shore, when the ship isn't anchored at a dock. You'll use them in Cabo, to get to shore and back. In Mazatlan and PV, you tie up at shore, so, I don't think you'll use them.
PV has a wonderful downtown, with a very cool cathedral. You can also do down to where they filmed "Predator" and take a jungle tour.
You'll also see references to Richard Burton and Elizabeth Taylor, in town. They met in PV during the filming of Night of the Iguana. Part of that set is still around too, south of town at the La Jolla de Mismaloya resort. It might be cool to rent the movie before you go...you might recognize some things when you get there.
Caution: I would not swim in the ocean at PV...it's very rocky under the surf line because of dredging after storms washed out the beach. Plus, PV still dumps untreated sewage into the ocean.
Mazatlan is the shrimp capitol of Mexico. Be sure and take the tour over to Stone Island. There are several bar/restaurants. My favorite is Victor's. Victor and his wife Alma are very cool. He speaks pretty good english...she tries really hard. Take a good book, pull up a hammock, stick your feet in the sand, have a cold one and have them cook you a red snapper on their grill.
You can also do a banana float ride, ride horses, play volleyball, and walk the beach at stone island. (Stone Island, by the way, refers to the island, just off shore. You are on the beach of the mainland, just south of where the cruise ship docks. Sometimes you can find sand dollars, too.
By the way, Mazatlan treats their sewage...so, it's ok to swim in the ocean...plus, their beaches haven't been washed out by storms.
If you want more information on other attractions in PV or Mazatlan, just drop me an email. I love those two places....and, visit about once a year.