I did a 3-day rental out of Las Vegas last year and had a blast. It was at the very end of January and the weather was suprisingly good. Highs in the upper 50's, low 60's.There's so many cool areas around the Vegas area. Red Rock Canyon and the Hoover Dam are both just barely outside of the LV area and must sees (on opposite sides of the city of course). I would highly recommend riding up through Death Valley to Furnace Creek. I road around Lake Mead and did Valley of Fire park on my way up to Zion National Park. I *highly* recommend Zion. Since it was still January, some of the roads in the upper parts of Zion were still iced over at the time, limiting my park access but I still had a great time. By April you should be fine.