I made a similar change when I switched from equitation to eventing (boy, was that ever a culture shock!). So, of course, I now do both jumper and dressage shows for practice and I enjoy the atmosphere of the jumper crowd much more than the hunter and equitation peeps. You should be fine if you've been showing on the hunter circuit for a while -- jumpers is a welcome relief! You should still have a regular rhythm in the jumper ring, it's just a little bit faster tempo! Don't sweat the distance if at all possible -- almost all shows are at least two hours from my area. Just try to schedule your shows economically, taking into consideration entry fees, travel time, etc. Your mare's a beaut, reminds me a little bit of my gelding in the face and neck. Good luck!
"Horses are self-portraits of their riders. Autograph your work with pride!"