In reference to the bunkhouse....not sure why you would want that for just 2 people. the bunkhouse is going to use up real living area that you will want if traveling for a period of time. Even if you add a thousand pounds of stuff, a 150 will tow it...with proper hitch setup.
Fifth wheel vs. travel trailer....you will get mixed opinions. They say 5ers are easier to back. They are taller, heavier, take more gas $$$. They take up your truck bed space where you could carry bikes, EZ Up, grill, etc. But you will get a higher ceiling + maybe a ceiling fan :-) So many decisions!