Rv for bathroom and kitchen?

I have a mancave with a twin size bed so I can sleep in it, parents and I live out in the country on their own land so I know it's legal but is it a good idea to have a small travel trailer to use the bathroom and kitchen so I don't have to share the extra in the parents house? I don't know why I didn't put a bathroom in it beforehand I should have saved and did that.