I was wondering if entry fees to a Poker Run such as say " Support the Troops" can be claimed as a charitable contribution and tax deductible? If so, how about related expenses like gas, room and board, meals, alcohol, etc?

I would check with your CPA but I know everything I did with my boat was deducted because it was listed on my business properties.

The best way is to sponsor through your business and most poker runs will cover your entry fees. Then you can use it as a marketing expense. At least that's how we structure our sponsorships.

Two issues I see..........

You are paying the organizer of the poker run who in turn donates the $$ from the organization to the charity.
You also have to deduct the fair market value value of anything you receive from any donation.
MWBP SOT is $250 and you get 2 breakfasts and 2 dinners and 2 Tshirts worth around a $100.

Fuel , hotel, meals, etc are only deductible if it is business expense.

You would be correct if you were writing it off as a charitable donation. Since sponsorships get a ton of exposure in marketing most sponsors write it off as an advertising expense. You get on all the social media, tee shirts, websites, and banners.