I read the first few chapters of this sci-fi book in 1985, when I was 11 or so. I feel like it’s a slightly older book, maybe from the 70s. Maybe older, but I don’t think so. A scientist is building a doorway to another reality in his laboratory. This is in his house and his neighbor is a nurse, a little pushy, crushing on him and always coming over. Well, he gets the doorway working one day when she comes over with a casserole (I remember this specifically) and when they go through the door into this new reality, they eat the casserole on the banks of like, a creek or something, with their hands because they have no utensils. That’s as far as I got before I lost the stupid book and it’s been driving me crazy for years! What was it called!
Lost Classics of Teen Lit: Name That Book! 