If you're in Amador Co. the area around Winnemucca Lake or Round Top Lake. is prettier than Showers Lake and is very suitable for a beginning backpack trip. As of early August the wildflowers should still be pretty good too. My recollection is there are camping restrictions in this Carson Pass area (Carson Pass management area) and you have to camp in designated campsites or such (and there may be some places you can't camp), so check on the various specific regulations. Winnemucca is also a pretty good lake for fishing because it has fairly numerous brook trout that, although not very big, can be fairly easy to catch owing to their numbers. Emigrant Lake (Mokelumne Wilderness reached from Caples Lake) is also a good choice and it is outside of the Carson Pass management area. Last I heard it has pretty decent fish (bigger than Winnemucca, not as numerous, but numerous enough to give your kids a good shot). If you are considering west side Desolation Wilderness sorts of trips, as I see with your Loon Lake query, I think going out of Wrights Lake to Twin Lakes is better. There is a nice recent trip report from Twin Lakes:
http://www.highsierratopix.com/communit ... =1&t=16289
By early August the Loon Lake area is lower and hotter because its elevation is low and it is a moderately long hike (~7 mi) to reach the Desolation Wilderness boundary near Rockbound Lake, although the elevation gain is pretty minimal. Moreover the area you cross before getting to Rockbound--the Spider-Buck Island Lake area--has a fair number of crowds that come in via the Rubicon jeep trail. In contrast Twin Lakes is less hiking distance, with a bit more elevation gain (but still pretty mild) than Rockbound, and it is higher and cooler. The fish, although much smaller than those in Buck Island and Rockbound, are much more numerous and easy to catch in the Twins, so they'd be more fun for your kids.
Advice? I have in fact backpacked with little kids, beginning when ours were small enough they were carried part or all the way in our backs, but this is not to say that my advice will be useful because every kid is different.
I would recommend taking the kids on a warmup hike before the backpack trip if they haven't been hiking this summer yet. If you haven't hiked much with your kids do not overestimate their hiking capacity. It is best to err on the conservative side if the kids are going to enjoy it. Unless you know they are super strong hikers I wouldn't go more than about 4 mi and 1000' of gain in a day and I also wouldn't have them carry much (ie you may have to consider taking their sleeping bags and stuff). I remember my first backpacking trip was when I was 8 and it was to Pear Lake in Sequoia NP followed by a climb of Alta Peak. The hike was no problem for me, so as long as I didn't have to carry anything. My dad had started me off conservatively by putting shoulder pads on the stuff sack with my sleeping bag (granted it was a pretty big and heavy one), but soon the sleeping bag was stuffed in his pack and a jacket replaced the sleeping bag in my makeshift daypack and by about mile 2 everything I had was strapped on my dad's back. I was a very strong hiker without load at that age but had trouble with any sort of a load. In contrast, my kids at the same age were not nearly as strong hikers as I was without a load, but they could put up with carrying a bit. All kids are different. Easier is better for the first trip. Your kids may prove to be super strong, but it will be best to raise the odds that they will enjoy their first trip by keeping the hiking and carrying mellow.
I would consider myself a fairly experienced backpacker and comfortable on and off trail although I prefer on trail most of the time. However since I'm with the little kids I'd obviously prefer a fairly simple trip. I was thinking of a quick trip to start, probably a short hike Friday evening to just get started and then 3-5 miles on Saturday and Sunday but shorter is fine too.
