There is a RV park in Fairview, on Sandy BLVD, that I spend a couple of months there in January 2008. It is a nice park, and they offer monthly rates. Electric was reasonable, with $0.10 per KW back then.
So for heat, I could have spent 22 KW at $2.20 or buy a gallon of propane for the furnace, locally for about $2.20 - $3.20 depending on location of the propane supplier. One on Division and 182nd was lowest that I saw locally for refilling portable tanks.
Sandy is a nice street, and fairly quiet, except the trains that go by the lower section of the park. I live within a mile of there, and closer to the train tracks.
I ran 3 electric heaters, one plugged into a #12 gauge extension cord to my bedroom through the basement to the sewer compartment and out to the power post 20 amp plug. My 30 amp RV will only support 2 electric heaters running on high if I shut everything else off. . . .
One small heater was near my fresh water tank, keeping my basement warm, and that is under my bedroom, keeping it warmer too. I set that one for about 55 - 60F. I refilled my fresh water tank on days above 40F, draining the other tanks too, and then putting away all the hoses. Local county ordinances require the use of a 'slinky' type sewer hose support if you plan on leaving it set up all the time, so that water will not 'stand' in the hose and start to grow bacteria. . .
Even if you only rent the RV park on weekends, this is a good one to consider each weekend, to dump your tanks, do laundry, then go park someplace else during the week while you are working.
There are several nice industrial areas where you might find a good place to park overnight. Google maps will find many in the NE 180th street area, north of Airport Way, or near it. South of Sandy, it becomes more residential streets, and not many people want a RV parking in their front yards. .
Fred.