If your going to lift it go w/ a tag along... If you get a auto tranny get something like the duramax w/ the tow haul mode so it doesnt HUNT like you say... As far as cargo space for a 14' sand rail you can get that into a 24' front kitchen toyhauler w/ no problem... It's all depends on what you like and what you can afford... Diffrent brands have diffrent Qualitys... again the brand war chevy vs ford who makes a better product... Just do your research and remember there is NO RV/TOYHAULER that WONT have any problems... If there is they would be selling like hotcakes and cost just as much as your house... and you would be on a 2 yr waiting list...
Depending on the size of trailer you choose to fit your needs will determine wether or not you need a 3/4ton or 1ton.. Is this truck also going to be a daily driver? IF it was me i would personally go for a 3/4ton CC S/B 4wd Diesel w/ a 26' foot Front kitchen/bath trailer as they yield the most cargo room and have a spacious floorplan...