Houseboats tend to concentrate activities on the aft deck and swimming platform areas, so it would seem an excellent idea to approach welcoming sandy beach stern-to. Well, nothing is preventing you from doing so, but additional caution is required to avoid any damage to your boat. The significant danger is that your propellers are going to hit the sand before the hulls. You can raise the propellers to avoid this with outboard motors, but you will be at risk for your propellers and rudders hitting the sand with inboard engines. Mooring in Marinas is almost always stern, but the dangers of doing a similar thing on the beach make it a risky business. Something I would not recommend.