We, too, run a heavy duty cord from the pole's 110 to a heavy duty surge bar thru the bottom of a window, into which we have 1 laptop, power speakers for the TV, air card router,electric heater, and rope lights for the awning....
...1 half of the 5er is on 1 circuit the other side on another...slide side, I have a desk lamp and the other laptop, the other side is where the coffee pot and the TV are plugged in......we never, ever plug in the toaster, etc. unless the coffee pot is off (TV runs okay with the toaster going.) ....for the toaster/convection oven (and when we had an ice maker), we run another heavy duty cord and surge bar outside for them, under the awning, covering them with plastic table cloths when NOT in use...Petula and the palm tree are plugged into the outside set-up at night....Ernie's Uncle who is a certified electrician, helped him plan this set up as we needed the extra power, but wanted it to be safe....all connections are wrapped with electrical tape and plastic.....It takes a little time to do, but when we are in one place for long periods of time, its' worth it...
.......Old propane tanks, as stated, may give you issues.....so re-fitting them and your hookups is a good idea....in freezing temps, if you don't have heat tape, either un-hook your water at night or let the water drip when you have sewer hookup....
We've been full - timing for 6 yrs. and have learned alot during that time and we're still learning....be patient....listen to all advice given....take what makes sense to you.... enjoy yourselves and Good Luck...It takes time to learn an RV, new or used,.....
You'll be fine...