I have a 2500/5000w Genpower pure sinewave inverter. Reasonably cheap, runs the aircon .... for a few minutes, anyway
The Princess uses the hairdryer occasionally. Has been reliable, although its not a daily appliance.
Ive got a 20.63.1OB and its in the front tunnel boot mounted, vertically on the internal wall. Our club lounge is directly behind that spot so it was easy run the battery cables straight through to the battery under the couch. Access to the inverter is simple from the offside tunnel boot hatch. I have a permanent GPO wired from the inverter and mounted next to the Setec inside the van.
I can also open the tunnel boot hatch, run a short lead from the inverter, externally, to the van GPO mains input and power the whole van, particularly handy for the microwave. I can find some pics if that will help
@mfexpanda has a similar, but much more integrated setup in his Silverline (the biggest, shiniest and most luxurious van. I once almost got a look inside, but unfortunately didnt have slippers and I hadn't had a shower in the previous 5min, so I missed out)