Designing a guest house is adding more floor plans space to your home, which gives you an opportunity to be a gracious host to friends and relatives, who visit often. It gives you an opportunity to include all those things, which you always wanted to inculcate in your house plan, but couldn't. Before you start making your own plans, you need to have a clear idea about the budget which you can afford to allocate and the dimensions of the piece of land, on which you plan to build it.
This will help you in creating a plan, that is customized 3d floor plans to your requirements. People opt for small guest houses, that are generally built on adjoining extra space of land. Of course, you could also be planning to build one, which is built farther away and doubles up as a weekend getaway. You don't want to make it too comfortable or else, your guests would never plan to leave.