You have more than you need. XC skiing is really great, esp. on groomed trails. A lot of upper body muscles used are similar to paddling. You can usually get in a few races or loppets too [it sure worked for knut Holman]. Snowshoes can be a killer if you don't have the legs, but are a great aeobic workout.
Strength training should be specific as possible. Chin-ups, shoulder dips, push-ups, abdominal work [most important]. With free weights you can do upright and bent-over rowing. In general, a lot of weight isn't needed because strength training is supplemental. A 300 pound bench press won't move the boat very fast, from what I've seen.
Plyometric movement is great for explosive power for legs. They can cause injury if improperly/over done. Shoulders are complex joints that take a long time to recover from injury.
Regular stretching overall is very important. It will improve full range of movement and balance.