Having come up from Lubbock and Amarillo in the past, I would go with the 287 to Limon also. Watch the Weather Channel and keep in mind that a wet spring storm can close the entire eastern plains. Be very mindful of going down Floyd hill (start the decent at 35 mph) and coming out of the Eisenhower tunnel (also start at 35mph) Parking will be tight in March, if your friends don't have space you should be able to overnight in the Gondola lot with not many questions asked. Carry a shovel, some chains and a few bags of cat litter to be safe.