Hi Evan! Sounds like you're in for the Disney adventure of a lifetime! I must say that I'm a bit jealous of your amazing coast to coast Disney vacation! Sounds like a dream!
To answer your question, Yes! You will certainly have no problem combining both of your vacations onto a single Photpass CD purchase, but please note, that the Walt Disney World pricing will apply to your order, not the Disneyland price, which is a bit less expensive.
The best way to secure your purchase is by taking advantage of the special the
Photopass Pre-Arrival Offer. Using this link to
pre-order your Photopass CD will offer a substantial savings on the purchase ($119.95 vs. $169.95).
Just keep track of your PhotoPass cards from both Disney World and Disneyland, and be sure to enter each code into your online Photopass account before finalizing the CD order upon return from your magical vacation!
Best Wishes,
Amanda F.