As the weather outside may be miserable and its hard to get out, I love to get on the rowing machine and rack up the meters! If you dont have a concept 2 rowing machine most gyms have a couple. Also check out Paddle Sport Training and you can get a SUP or Outrigger adaption for the C2. The adaption works awesome and we use it regularly in the winter and to train with watts (power)!
2min jump rope, 25 push ups, 50 sit ups, row 500m @ 60% (talking pace)
8 x 750m @ cant talk pace but not killing yourself, recover 2:00 (easy rowing), hold each effort within 2-5 seconds
500m row @ 50%