Yes to both. Riding horses actually works your whole body, though not as much as real, full body strength conditioning. It's excellent for legs and core muscles though. And a trampoline is actually great for cardio, if you can keep it up for 20-30 minutes at a time. You should also watch diet if you're loking to drop any extra fat. Exercise is great, but a bad diet will easily ruin your efforts.
Keep your body lean, your blood clean and your mind sharp. -Rollins