I'll assume you know it's still very much "winter" in the alpine Rocky Mountains in mid-May. Many of the roads that lead to marked 3-season campgrounds & trailheads are burried in snow and not open to car / truck travel to those trailheads - some are open, some are gated & locked. It would be best to call the headquarters of the San Isabel National Forest and try to talk with one of the Rangers for vehicle access.
The northern, central and front range mountains are having a very good spring snow season. We've had nice snowstorms for the last 4+ weeks in a row - with another 12"-18" today, lots of new accumulation - also a lot of avalanche and high potential for avalanche. Always check in with CAIC (Colorado Avalanche Info Center) and of course don't go into areas without proproper skills and training for reading the terrain, snow travel & rescue.
The alpine in the Massive / Elbert areas are 30*-45* round-ish wide open and windswept - perfect avalanche terrain. There is not a lot of people going in those areas at this time of year, so not a lot of reporting of conditions. Plan on using floatation devices - soft snow in the trees will be knee to waist deep, windswept dry to multi-foot high drifts in the alpine - it will be very wet melting snow conditions in mid-May.
If you don't have it - I would highly recommend Lou Dawson's backcountry skiing guide book - one of the best references available for backcountry winter travel - I don't remember if the Mt Massive area is included - using that guide and using one of the descripted routes as a plan "B" would be a great idea.
Have fun - Be safe!!