My suggestion is to reach out to the facility that you are staying the 50 nights (I assume that you are looking to staying at the same location) and talk to the sales person there. Perhaps you can negotiate an immediate status upgrade there since they know that you will be at location for x period of time. So, you can start "strong" by having platinum status rather than complete the challenge and then get your status upgrade.

Just remember, it never hurt to ask. Worst, they say no and you continue with your challenge.

l8r

-doc