Me and 10 other of my friends are planning a trip there June 13th-20th. We've been there once but only for a day 2 years ago in May and even though it was wet and cold, we thought it was spectacular. We plan on tent camping, but have no reservations so we plan on taking a gamble with the first come first serve sites. During the week, half of us are planning on conquering Half Dome along with other day hikes. So I have a few questions for you guys and any help would be greatly appreciated.

1) Which first come first serve sites will be open for us? What time should we arrive to gurantee us 2 spots that are adjacent? Any strategy for getting a campsite?

2) Will half dome cables be up then? Do you think there will be a traffic jam on the cables around that time?

3) What are your recommended day hikes that are under 10 miles round trip (for my other fellows who aren't in such great shape). Are there any night hikes to a beautiful summon where we can relax at the top?

The only first come-first serve campsite open then is Camp 4.

All the others don't open until July.
http://www.nps.gov/yose/planyourvisit/campground.htm

And this year... who knows when in July.

Cables def. up by then... logjam? I would count on it...

Easiest "summons" is Sentinel Dome.

I assume you mean summit. I would say that Upper Yosemite Fall Trail is less than 10 miles round-trip. It's also a pretty large elevation gain but I think most people could do it.

If you want first-come first served campsites, apparently Camp 4 is the only option in Yosemite in June.

One option might be the KOA in Midpines - along Highway 140. Right now they only seem to be reservable from June 13-18 starting at $40 for two people. You could reserve that and then try a 1st come 1st served site in Camp 4 on Thursday or Friday morning. At least with the KOA, showers will be included. Showers in Yosemite are $5/person.

As for the Half Dome cables, I'm guessing they'll probably be up by then, but anything is possible. You'll need a day permit now Friday, Saturday, Sunday, and major holidays. No permit would be needed on other days. I understand that the plan (the permit just started and they haven't actually implemented it yet since the cables aren't up) is that personnel will be stationed around the Sub-Dome to check for permits.