There is a lot of information on the web-try nolo press. They also publish great books, relatively cheap. I also wrote a 27 page report on this subject for soapbox, which never sold so I deleted it from the soapbox site. I would be more than happy to email it to you at no charge. (I think you have posted a lot on the REHP which I have benefited from, so I would be happy to repay the favor.) It will cover a lot of the questions you ask. Briefly... I would think twice and then think again before I would go into a partnership with anyone. Too much liability. An LLC would probably be your best bet. A subchapter S corporation would be your next best bet. Assuming you were flying to the mainland for business there would be no reason you could not take the deduction in full. Just be sure to document the prurpose of the trip, etc..etc..There is also a great book out "What the IRS doesn't want you to know" written by a CPA, Marty Kaplan. Its in paperback and worth buying, if you can't find it at the local library. good stuff, even for non tax types. I will try to post tomorrow all the web sites I used for my research. Hopefully I didn't delete all of them.