I think the problem with doing the rides together in one ride is the same issue with any 'nested' rides. If you did a 50CC Gold, riding 2900+ miles in 50 hours, you pretty much had to have ridden a SS2k in the process. Because of that, you can't claim both rides, as I understand it.
You live in NV according to your profile. You're planning your 50CC Gold for May. Take a weekend and do a SS2K ride and submit it. If queried later about your 50CC Gold submission, just let them know you previously submitted the SS2k ride and when, but that it hasn't been verified yet. I wouldn't worry about waiting until it's verified and you have a cert hanging on the wall. The point is to make sure you know what you're in for and hopefully are prepared. 50CC Gold works out to a min of 58 mph average speed for 50 hours. A little less than a BBG pace. By comparison a SS1k is only ~42 mph. But it's about being able to function well on back to back full riding days.
Doing a 50CC Gold or back to back BBGs is partly about preparation, partly about focus and partly about wanting it enough to keep going. May can be wet, cold and miserable in much of the US. Heated gear, hydration system, a solid routine for gas stops and a very good knowledge of your bike's range under varying conditions will help greatly.
Good luck, plan the ride, ride the plan, be prepared to modify the plan on the fly.