Next-to-last long run before my Labor Day weekend half. Got my second wind the last 2 miles and felt tired but good at the end.

Question for you experienced runners: how should I structure my training between de Labor Day half (Sept. 6th) and my Lake Powell half on Oct. 17th? Currently I run 3 miles two mornings a week, and for the weekends I alternate between another 3-4 miler one week and a long run the other week. My long runs have been increasing by about 1.5 miles each time, I'm up to 11 miles today. One more long run in 3 weeks (have to work around a bike event in 2 weeks) before I taper. So what length runs should I be shooting for during the 6 week span between the 2 half marathon events? Should I schedule in another 11 and 12.5 miler (which honestly makes me cringe) or can I make the long runs shorter to avoid burning out? As you may have guessed, I'm not running for speed, just to enjoy the events and finish.