Welcome to the forum. The rake is the same. You can go with a full 3 up front and 2.75" in the rear to keep level and clear those wheels easy provided the stock backspacing. The bump stops from timbren will be expensive and no better. Get the energy ones for cost on eBay and mint them to the lower. Your cv's will struggle in the front with the full 3" so plan to do something to prevent the rapid boot tear and horrible angle.
Ha. Is 18' not small for a travel trailer? Being from CA (now in MA), 30 foot toy haulers were the norm.
Ugh, CV angle issues at 3" is something I want to avoid. That is exactly what started the snowball/money pit that my Nissan turned out to be. Before I know it, I'll end up like the guy on this board that wanted to replace his air bags but ended up going LT.
Any way, if I can get away with 2.5" in the front and 2" in the rear and still fit the slightly wider and slightly taller tires then I can live with that.
Btw, I don't know the stock specs of the stock Z71 wheels but the wheels I may purchase are 17x8 and have an option for 10mm or 25mm offset. Will either retain "stock" specs?
For the rear, is there a rule of thumb for spacer height that relates to actual lift?