Two electrical concerns, voltage and Hertz. European is likely 2220-240v, which can be had from US 50A campground power, but the US Hertz will always be 60, whereas European is typically 50. US 30A power is 120v only and no way to adapt to 220 without a transformer. There is probably a physical plug difference as well, but that should be easy enough to adapt once your plug configuration is identified.
I don't know what sort of water line connection your coach has, so maybe a water hose thread difference as well? I think th UK uses BPT (British Pipe Thread) specs, but not sure about the rest of Europe. US hose connections use a 3/4" threaded connector with a unique thread type, different than US NPT (National Pipe Thread). It's called "Garden Hose Thread' and is a non-tapered thread with 11.5 threads/inch.
I don't think you can make the trip you described in 8 months, and even a year is pushing it. Unless you just plan to just drive and never actually stop and see anything. For example, from Seattle Washington (near the Canadian border) to Santiago Chile is about 6500 miles or 10,500 Km. That is air travel distance, and driving distance is probably 50% greater. I think you are planning to drive more than 30,000 miles (48,000 km), much of it over local roads in mountain terrain.
As others have said, you could easily spend a year crossing the USA along the Canadian border and then returning via a more southern route. That would typically be a 10,000 mile (16,000 km) journey by itself, with sight-seeing stops too numerous to mention.