PC couch gaming advice?

I'm coming to you guys for some advice on how to start playing PC games on my TV. My mancave is a rectangular room, about 20 feet lengthwise. My PC desktop is on one end, and the TV/consoles/hometheater on the opposite end, with the couch stretching right across the middle.

1) Could I leave the desktop on the opposite end of the room, and run HDMI all the way across the room and back into the wall into the receiver? Looks like about 25ft of HDMI. I heard HDMI cables don't run that long due to attentuation issues or something? Is there any kind of wireless HDMI solution I could use?

2) What do you guys use to play keyboard/mouse games from the sofa? I've got a coffee table that lifts up and forward so that you can eat off it, but I'd have to sit on the edge of my sofa the whole time. I use controllers where it's comfortable, but some games just play better with a keyboard/mouse. (Maybe I just need to wait until Valve starts selling that new controller at retail before I make any move to play on my TV).

I'd appreciate hearing some suggestions, or just hearing how you guys have setup your media center for PC gaming.

The distance between my tv and my computer isn't nearly as long as you're proposing but I am running a 25 ft. hdmi cable to my tv and it works fine with no issues of any sort. For your other question the website Tested actually did a 2 part piece on this very subject matter.

http://www.tested.com/tech/pcs/456702-living-room-pc-part-1-no-keyboard-no-mouse-no-problem/

http://www.tested.com/tech/pcs/456792-living-room-pc-part-2-keyboard-and-mouse-problem/

@i_stay_puft:

Thanks! I'll take a look at those links.

The PS4 controller with the latest wrapper (beta 3) has touchpad support so you can use that as a mouse.

I use this bad boy for my couch (well, bed) computing.

You should try out http://touchmote.net/ it seems like an awesome solution, assuming you are on win8. I haven't personally gotten to work more than just use it as a way to use my classic controller on a snes emulator, but other people have supposedly gotten it to work. Having said all that I, too, use @bbalpert's suggestion.