We had a 2012 Roo 19 (identical to the Shamrock) for 3 years. It was a great hybrid. Wife just got tired of folding up the bunk, and I always had to climb over her to hit the bathroom in the middle of the night.
You want to make sure there are no signs of leakage. This includes looking for delamination of the fiberglass under/around the bunk opening, as well as the bunk itself. Check out around the water filter (behind the front street side outside access door) for signs of leakage. The water heater hot/cold/bypass valves were small brass versions (see pic). I ended up replacing 2 of them with plastic ones, as the brass ones are junk. Look around the shower. Most of us install plexiglass on the wall of the bathroom cabinet that faces the shower to protect it (see pic) and a large corner splash guard (see pic). If these have not been done, inspect these areas well, and seriously think about doing it yourself if you do buy it.
1988 Coleman Sequoia - popup (1987-2007)
2012 Roo19 - hybid (2012-2015)
2016 Mini Lite 2503S - tt (2015 - ???)
2011 Traverse LT, 3.6L, FWD
2009 Silverado Ext Cab, 5.3L, 4x4, 3.73
2016 Silverado 2500HD Dbl Cab, 6.0L 4x4, 4.10