try to stay as light as you can inside the house... leave the xtras in the truck when moving...
the suspension on the bigger houses works pretty well, but be careful on washboard gravel and especially getting on or off the ice if it's rough...
when not traveling far, i would drop air pressure in tires to 15 to 20 psi to add some more suspension...
if not buying from a dealer or manufacturer, be careful... regular axle ratings don't really mean much if your axle is not stock and engineered... anyone can weld a different spindle on a tube and mount a 7k hub on it... standard bolt #'s mean nothing on anything home built... on anything used, i would crawl underneath and check for anything bent or new paint on welded seams...
aluminum is light, but weaker than steel... if you buy aluminum, take care not to overload...
spray foam is always worth the money if you can find it and swing the added cost... it increases racking strength 400%, and will not sag in the walls over time... be sure foam is closed cell and not open cell...
congrats, good luck, and have fun...