RunningAh, running, my love. And boy do I love to love and hate it at altitude :) I'll admit, I have yet to run more than 10 miles in Big Bear in one run, but it'll happen one day. Of course, you can run on any road around town, but here are a couple recommendations.
For a flatter asphalt path with a scenic view, take the North Shore Trail. You can park for free by Vons or on the Stanfield Cutoff bridge area (and avoid paying fees at one of the nearby lots on the north shore!), and from there it's a quick jog north and then hang a left onto the trail. Can't miss it. If you hit the 18 highway, you've gone too far. I'm actually not sure how far the trail really goes, but I've run an out-and-back on it for 6 miles total (t-run). I think it goes another mile or two before turning back into the main road with cars. It is really a great little trail, and there are always people walking an jogging, but there's ample space and it's not too congested. My 6-mile run only had ~200ft elevation gain. And this is at ~6,700ft btw.
This area is also where the hold the Endure the Bear trail runs (everything from 5k to 50k I think). The route will take you all the way to Snow Summit peak, which is about 8,000ft. Next time I go back, I'm going to do that... I'll probably do the 15k or 30k route, which you can check out here . I was actually going to do the 15k this past week, but got mixed up on the route and then after rolling my ankle decided to to do anything too crazy in case it started hurting worse.
My friend Ryan Denner, who knows this area very well, also recommended the Cougar Crest/PCT trail on the north end. Sounds interesting! You can find many more trails on Strava and Map My Run.
That's it, for now, for swim-bike-run tips! And last but not least...
EatingFood. A must if you're kicking arse in las montanas! If you're looking to be super healthy, I suggest bringing your own food and staying in a cabin with a kitchen (or packing a cooler if it's just a day trip). There are plenty of bar/tavern/mountain-style places with typical American fare and plenty of pizza joints, but there aren't that many health-oriented restaurants from what I've seen (including on Yelp/Google), and the "good ones" look a little pricey and possibly just open for dinner. And during summer, open hours may be even more limited? That said, there looks to be some better places in The Village area, with more opening. I want to try this one .
Grocery-wise, there are only two main stores: Vons (the better of the two) and Stater Bros. That said, I usually stock up on groceries before leaving so I'd have all my organic, grass-fed, healthy stuff for our meals, down to quality cooking oils to avoid food that may promote inflammation. Plus I love being in a little cabin cooking the mountains -- adds the the experience!