Welcome...I find that with regard to leveling I know how much extending my slides will affect my level so I level the trailer first taking into account how much extending the slides will change the level...if that make sense. I.E. the trailer will be slightly unlevel until the slide is extended which saves having to, in my case, move the trailer with the slides out.
Tim & Jenn
2009 Forest River Grey Wolf 235 5er
2003 F-350 Superduty 6.0 l Diesel