I have the 3150 BHD also and love it! Without repeating all of the great replies, I'll add that it's useful to have some of those disposable latex gloves for the sewer dump time. As for wheel chocks, keep in mind you have a 17" spread between the wheels if you go with a scissor style. I just use the plastic ones and they work fine.
Get yourself a couple of inline LP gas meters from Walmart ($12) and put them on the tanks under your cover. Helps to know where your at at a glance.
IMHO a must have was an electric jack. It only took me 2 trips to the dealership (for upgrades) and they begged me to put one on because the service tech hated cranking that 34' trailer up. After the 2nd visit they gave me a nice discount!
I added a Air Maxx 2 in the back bunk over the vent. You'll find that the AC unit struggles to push back that far. It pulls the air from the front out or visa versa.
If your DW wants to use the oven, get a baking stone, or learn to like burnt biscuits.
There are more nice-to-haves that I could list here, and to each his own on what they consider camping vs. hotel on wheels.
My ol lady is the hotel on wheels type so we have spent $$ on little enhancements that most would laugh at!
Enjoy! Nice to hear another 3150's out there!