Sounds like a cool plan. What kind of cycling is the death valley thing? If it's 105 miles then I assume it's road biking.
For tattoo ideas.......... a big cactus with skull and cross bones hanging on the front, but instead of bones I'd use syringes. The cactus is next to a crumbling road trailing off into the desert distance (tumbleweeds, sand, cacti....). If I could draw this would be easier. Oh and the skull has to have an evil smile, because no one in their right mind does that kind of ride.
I did a similar ride last year, 115 mile circumnavigation of Lake Okeechobee down here in florida (L.O.S.T. = lake okeechobee scenic trail). I did it solo and unsupported, just picked up water at gas stations along the route and carried all the "food" i thought I would need.
My best advice would be to stock up on energy gels (clif shots, gu's, etc.), they have a good energy density but they don't last too long. A complex carb mix drink (I've had good results with Infinit Nutrition drinks) is something I'd take with me if I do it again this year.