There was a thread on this very subject not too long ago, check through the older postings.
If you are using the mast hinge, you can safely hold the mast in place with a spare line. What I used to do while rigging with the boat on the trailer - mounted a block on the trailer (I put it on where the trailer mast support mounted to the trailer), ran a longish line through it - one end I attached to the main halyard, the other end on the tramp, or tied off loosely on the mast, with the mast hinge pinned and the shrouds attached, lift the mast up into place, then pull the line on the tramp to take up the slack to hold the mast in place, and tie it off around the mast, now you can go forward and attach the forestay.
If you are rigging your boat alone on the trailer, make sure the boat is still strapped to the trailer, and make sure the trailer is safely latched on the hitch. If you can have the bow facing downhill it will make things easier.
If the boat is off the trailer, you can do the same kid of a thing with the bridle as the place to put the block for the stabilizer line.
Now, hooking the forestay goes easier if you have loosened one of the shrouds, which of coursre, you need to re-tension. As mentioned above, you can do that with a trap wire, attempting to hold it with your harness or your hand. Honestly, the trap wire method should only be done if you have someone else there to hold the trap wire while the you mess with the shroud. It's too easy to drop the pin or the mast doing this alone. The easy way to this is to go ahead and raise the main sail, then move the traveler car to the side you want to adjust the shroud. Then sheet in hard - the main will support the mast, leaving you free to adjust the shroud as tight as you want, the harder you sheet the main the more slack you'll have to play with on the shroud.
If you don't want to raise the main before you adjust the shrouds, once again you can use the main halyard - although this may take a little creativity on the 14, as the boom is usuallly left with the sail. You can use your mainsheet system - unhook it from the boom, hook it as normal to the traveler car, hook the halyard to the boom end of your mainsheet system, then proceed as above.
