Demigods of the Falls

Ok, ok. I may be a bit crazy to do this, (well I am crazy) but I wanted to do a gravity falls and Heroes of Olympus crossover. (Reverse Falls exists too btw) I plan on adding a OC made by one of you amazing readers, so stay tuned for when I ask for that. Basically though the 7 (from HoO) meet the mystery twins and other characters and have to defeat monsters, Bill ( yes mighty dorito will be there, and I have plans for him. Big plans) How do they (the 7) get to gravity falls exactly?? Well you will have to read to find out! (also this is my first fan fic so yeah)