I've slowly been transitioning my interior decor to a
Disneyland theme. The primary bedroom is Big Thunder Mountain Railroad/Frontierland, so it has elements that feel "Old West." I've purchased items gradually as the budget allows...a duvet cover from Crate and Barrel, a large print/photo from IKEA, switching out the bedside lamps to ones that feel appropriately rustic, that sort of thing.
Our guest bedroom is Adventureland. That room is finished and I'm really happy with how it turned out. I'll post some photos of it later when I have the chance. Bought a sign off of Etsy, a print from IKEA, some old items of DH's grandfather (who collected some trinkets in the South Pacific in WW2 while serving in the merchant marines), etc. Curtains in that bedroom are linen and are there more for decoration than anything else. Duvet cover has a tropical feel to it without being too over the top.
Guest bathroom is the Enchanted Tiki Room. That has an item or 2 in it from DH's grandfather, along with a framed postcard of Adventureland/Enchanted Tiki Room from Disneyland (got the postcard there for cheap, bought a bamboo-ish picture frame at a store near home). Bathroom window covering is a rattan shade. Shower curtain is Tiki Room-themed that I bought off of Etsy.
Family room is a mish-mash of Disneyland stuff, but more centered around DL park rides. A few years ago, a Disney friend at work gave me a bunch of her calendar's theme park ride mini-posters, so I framed those for cheap and they hang all in a row above our couch (Matterhorn, POTC, IASW, Peoplemover, Mr. Toad's Wild Ride). On another wall in the family room, we have 3 different DL silhouettes hanging: 1 of my sister & I when we were kids, 2 of my kids from different trips; plus the Club 33 key we bought the one time about 6 yr ago when we got to have lunch at Club 33, a DL ride print signed by Bob Gurr, plus a Haunted Mansion sign and a POTC print. And I've got a tall-ish standing IKEA lamp next to the couch in that room...the lamp feels Tomorrowland-ish.
Eventually, once YDD is off at college (she's in 11th grade) and when she's closer to college graduation, I'm going to convert the kids' bedroom into a Tomorrowland theme. Not sure yet if I'll put twin beds in there or a queen bed, but the furniture will definitely have a midcentury modern/1960s space-y vibe to it, with lighting & other accents to go along with that like:
Space Mountain light up sign
Peoplemover sign
Monorail art
and a clock like this but not this exact one because it's too expensive
In our dining room, it's sort of a mix of Native American art & Star Wars with dark woods (because we inherited some antique furniture of DH's mom). There's a Hopi artist I've bought some prints of and he's done some really cool stuff mixing Hopi designs with Star Wars stuff.
Here's his website in case you're interested. In the china hutch, I have several Mata Ortiz pottery pieces on display (I started collecting them several years ago). And the area rug in the family room is a big black & white cheap one from IKEA that has a geometric design which sort of goes with the whole thing.
Doesn't have to break the bank or cost an arm and a leg. Pick one room and start on it and work on it a little bit at a time. And eventually, you'll figure out what you want out of each room and when you find the right item to go in each room, you'll just sort of know.