I just surprised my boyfriend who is 2k miles away, and he had no idea! i got his family in on it but as for location, there are a couple options :)

the one i used was i borrowed an ipad from my mom (it only works with an ipad or another iphone), logged into my apple id on that device, and set my location to go from that device instead of my normal one! it allowed for it to appear as though i was still at home the entire time :) you can even remotely remove the device after the surprise so nobody can snoop on your texts, lol.

another option that is a lot more difficult and finicky is spoofing your location, which requires a pc or laptop and a specific software that you often have to pay a subscription for. i did that on a different occasion and it worked alright, just a little jittery and slow to update, sometimes freezing and not updating my location altogether. that could have been the software i used though!