I've been doing my long runs partially on a treadmill (because I hate running in the dar) and partially outside. Can I combine the two into one run?
Yes, assign the functionality "switch activity" to a button and then you can easily perform outdoor run and and indoor run. Just tried it, worked perfectly.
... or you can prepare a multisport profile in advance, if you know what kind of activities and in what order you'd be doing. This way switching sports is even easier.