I realized years ago when hiking or night swimming or making plans generally, trying to get people to go with you, "scheduling", all that, its crap.
Instead just say "I am climbing Mt. Moose. If you want to come be at the parking lot of Yam cafe at 6am Sunday." Wait on no-one.
Surprisingly, this gets more people to come
PLEASE, get comfortable with going to events, movies, concerts, coffee shops, museums by yourself so you don't miss out on life waiting on people.