Oh geez....this would be a lengthy reply and a long thought process due to all of the variables of trails and also your goals and direction of travel want to be.
But to keep it simple I would say to start off on Clark’s Grade Rd. This trail starts at the base of the mountain and takes you all the way up with spectacular scenic views along the way also has great short side route options that take you to other cool views points then continue on up Clark’s grade once your at the end of the trail it splits off in 3 directions (routes) which all will keep you in safe keeping from not ending up on a hard/difficult trail. All are easy to moderate trails. Just remember all of your hard and difficult trails are on the north side of the lake and 75% of all big bear trails are easy to moderate trails.
It would be easier to tell you what trails to not go on and highlight those trails on the list since there is only about 10 that qualify not having any interest of yours and will keep you out of harms way.
Also if you go up to Bald Mountain Ranger Lookout Tower that would be an awesome and scenic trail route as well I think it’s still open to go up there and actually go inside the tower and check it out. There would also be a Ranger on hand there to show you around and explain its history and purpose as well as take in the 360* views like none you have seen up there before.
I know If you call the local ranger station they will tell you if it will be open the day of your travel or possibly check their site to find out as well.
