Welcome to the Forums. If you are set on the R-pod, the RP-175 seems that it would give you a little more space. Some things to consider are a permanent bed that can stay made up, and having the refrigerator up off the floor. A slide makes a huge difference and AC is pretty much of a must if you are planning on using it during the summer.
Happy Camping! ///// Richard D.
2006 4x4 Ford 250 SD / 2007 Flagstaff 827 FLS
One very patient wife and one furry child who travels with us. Forty-two years of trailering and camping, and I still have a blast.