Have you ever tried shifting into other gears before going into first? I have to do that in the morning sometimes. I just keep trying until it goes into something, then go back to 1st and usually it goes in easily.
That might be a few things. First off, check to see if the seal under the cap on the reservoir still looks good. If it's deformed, get a new one. Change your hydraulic fluid, it is likely contaminated with a small amount of moisture. I wrote hydraulic because you need to bleed both the brakes and the slave. I'd start with the passenger rear, then driver's rear, then passenger side, then driver's side, finally the clutch system. Use a vacuum bleeder, and be sure to have enough fluid on hand. Do not use Dot5. Dot3 is recommended, but check the owner's manual to be sure.
The fluid might be just old. Try pumping the clutch a few times before you try to put it in gear and see if that makes a difference. If it does make a difference, then you might consider changing your hydraulic fluid. I'd get a vacuum bleeder kit, and a bottle of new fluid. I think that would be a long shot- it's more likely to be contaminated like above.
Engine idle has more to do with getting in a gear than you might think. Try fluffing on the accel just slightly when putting it into gear. Yeah, I know, the clutch is supposed to separate the two, but that helped an old van of mine for some reason. Don't force it, just apply a slight pressure when you lightly tap on the accel. It should fall in without much effort.
Finally, and most likely, check your transmission fluid level since you are having problems with the transmission. You just need a level spot of ground to put the car on, then open the fill plug in the side of the transmission at the front of the engine compartment. It's an 8mm allen or 5/16 if I remember correctly. If it's low, just put a small amount of synthetic 75/90 in there- it shouldn't be very low. If you have to put a whole quart in, then I'd strongly consider finding the leak, and getting some Ford fluid for the transmission. The drain plug is in the back of the engine compartment under the dog bone mount. It is the same allen wrench.
