Oh ya... Sign Lady here... you definitely need to buy the rapid remover you will use it in places you never thought possible. the obvious decal goo removal, tape residue removal, sap removal, road tar removal, Silicon removal, I even used it to de sticky the walls inside my old trailer...its awesome stuff. Doesn't affect the clear coat either, I use it here a work daily and have used and entire gallon at home on my 69 argosy restoration. It removes the old vulkem.
You use it AFTER you remove the old stripes (a blow dryer or a sunny day helps heat the glue and ease the removal process) the rapid remover take the glue off. Spray it on 30 to 60 seconds scrape it off repeat if needed wipe the remnants with a paper towel soaked in the stuff. A quart will likely work for your newer trailer. It doesn't work to remove the newer lines of sealants.
As for the Ghost off. I got a sample from the supplier several years back tried it twice and well...it's still on the shelf... I use wet Mr Clean magic erasers for haze removing on vehicles at the shop.
Rapid tac is an application fluid for when applying new decals, you would likely not need it anywhere but if you do want to do a wet application of a decal you can make your own rapid tac. In a spray bottle, mostly fill with water, add two drops dish soap and 2 tablespoons isopropyl alcohol, add 5 mils Vanilla extract if you want it to smell as pretty as the original stuff. easy peesy...