Definitely riding 25 mi. will help your cycling more. If the elliptical has upper body paddles, you'll get more upper body on the elliptical. Elliptical is generally 500 cal./hr., spin bike can be from 500 to 1000, and I'd guess rowing is similar to spin bike. I've done many 1000 cal.+ hour rides on a Kaiser spin bike, and it is a massive effort, but it can be done. We just got a Waterower rowing machine, but I haven't had a chance to use it much yet. I've used Precor ellipticals for endless hours in the past, but difficult to get more than 500 cal.