Suggestions- looking to get into possibly an 80 series or 100 series, we tow a trailer about 2000lbs, plus the 4 of us which include my wife and 2 kids. Live in the midwest but venture to the west alot which obviously involves the mountains, can the 80 or 100 do this and travel 65 on the interstates and maintain speed limits through the mountains instead of crawl speeds. We love the scenic routes but sometimes we only have 10 days off so we would like to reach our destination at least at speed limits...