it somewhat depends on how long you’ve been riding; how many seasons and what type of mileage do you do?
Pending that answer, a nice diet of tempo and Sweet Spot during the week (1 session of each), with some longer endurance rides (75% ftp) on the weekend, and you’ll really build up an awesome aerobic engine.
While climbing hills helps you climb hills, some great climbers come out of the Netherlands, so all hope is not lost by using your turbo trainer. 
Let us know what you decide and how the training goes!
Cheers,
Brendan