No problem. Cabo is very easy. You will tender into the tender wharf and then you can simply walk into the downtown area (and also the beaches if you want) Just exit the tender wharf and turn to the right, it is about a 15 minute walk. If you want to go straight to the beach to party, you can grab one of the water taxis at the tender wharf and tell them to take you to the "Office".
Puerto Vallarta is also just as easy. Leave the port and turn right at the main road. It is about a 30 minute walk into "old town" where all the shopping, bars and restaurants are located. A taxi will only cost you about $5 OW. Just about everyone in both ports speaks perfect english, so you shouldn't have any problems whatsoever. If you want to walk into town along the beach in PV, simply exit the terminal and then walk into El Cid Hotel to the beach and turn left and follow it into the main section of town.
Have a great cruise!