+1 on all of the above. Also put modeling clay or even Play-dough into any recess in the action which could create a mechanical lock. Kiwi neutral shoe polish works great as a release agent for Devcon. Put a couple of good coats of it on, then remove the excess. You will be able to see very fine details transferred from the metal into the Devcon, and still get a clean release.
I like to remove the trigger, to reduce the chance of getting bedding material in there. It's easy to do, just pay close attention to how it fits together before you take it apart. Take several pictures from different angles, or ideally you may have another rifle with the same trigger to compare it to when reassembling. Put tape and/or clay in the trigger cutout of the stock too.

All in all it's not that hard. Just take your time, pay attention to detail, and you won't have any problems.

GaCop is right about letting the consistency thicken before using the Devcon; However, that applies mostly for people who are very experienced with using the right amounts of putty and hardener to achieve a slower set. The last thing you want is to be still applying this stuff into the stock when it starts to set up. I'd recommend for your first time to mask off everything really well, and thoroughly fill in any places you don't want the Devcon with putty. Make sure you have everything that you need at hand before you start. Mix the components exactly as the labels states, apply it in the stock, and get the barreled action in there as quickly as possible, then be ready to clean up any overflow. Be sure to thoroughly mask your stock with blue painters masking tape beforehand. On your first attempt, you will probably be a little slower and I'd hate to see you end up with hardening Devcon in there before you get the action in place. This stuff can harden quickly if you use too much hardener, so follow the directions. On my first one, I wasn't sure about how much it would take, or how to divide it correctly, so I mixed the whole 1lb. can. Turns out, this is enough to do several rifles, and all the excess was wasted. Experiment with smaller quantities before doing your rifle, and find the consistency and mixture you want beforehand. It doesn't take much to do an average rifle. With that said, make sure that you do mix enough the first time, and mix it thoroughly to avoid any soft spots from forming. You don't want to run out when you're applying it to the stock and have to stop and mix up some more. Lastly, I'd let the rifle sit overnight before attempting to remove it. A few sharp raps on the bottom and sides of the stock with a 1lb rubber mallet should pop it right out.

All this sounds kinda daunting, I know, but just take your time and pay attention to detail, and use common sense, and all will work out ok.

Edit:
Also, as 82 pointed out, do not use your action screws when you bed this rifle. The point of bedding is to remove stresses that can be introduced into the action by tightening it down into an ill-fitting stock. If you use your action screws to tighten your action down into the soft Devcon, you are simply setting a stressed action into stone. You want the Devcon to flow around the action while it is perfectly centered in the stock, positioned with the action holes centered over the pillars, and with plenty of Devcon between the rear face of the recoil lug and the stock recoil abutment, to form a new properly squared abutment for the lug. Wrapping your barrel with electrical tape to the proper thickness to center it in the stock will help with barrel alignment issues, assuming your stock is reasonably straight to begin with. Also be sure to use long 1/4" bolts that do NOT make contact at the head with the pillars, to place throught the pillars into the action screw holes to get the action centered properly. It helps to put a few wraps of electrical tape around the bolts where they go through the pillars to achieve true centering. Also coat these well with release agent, over the tape as well. Put modeling clay into the action screw holes to keep the Devcon out. When you thread them in, the clay will get pushed out of the way. Or, alternately, use studs with the heads cut off as 82 suggested, and thread them in place before you set the action in. Put release agent on EVERYTHING you don't want Devcon stuck to. Be sure to make a practice run with all of this to make sure all will fit correctly. Again, DO NOT TIGHTEN THE ACTION SCREWS. When the action is finally in place, dummy action screws are threaded in, Devcon oozing out around the edges a little, then use surgical tubing or electrical tape wrapped tightly around the action and stock to hold it all together while it sets. Clean up the excess now while it is still soft!

Good luck and let us know how it turns out!