Do it yourself!
It can be a pain, but it can also be a great joy too. I've learned so much doing my own drum to disc conversion, which required rebuilding my entire front end. I don't know if there's a kit per se, but you can get year/model front end rebuild kits which are all the bushings you'd need for a rebuild.
If you go urethane or rubber it depends on the stiffness of the ride you want. If it's a daily driver, more rubber tends to be better.
That said, there's a bit of a trick to front end rebuild kits - you can go with a full kit made in God-knows-where, or you can get part #'s and order made in the USA parts and bushings by Moog. And it gets trickier because some of the boxes marked "Moog" with the "Federal Mogul" or "National" logo are made in China. And working in a tool shop where you see a marked difference in quality between US, Europe, or Japan made products, I simply don't trust Chinese made stuff on high stress areas. Your bushings, control arms, ball joints, etc on the front end support a lot of the weight of the car as well as bear all the stress from the bumps on the road.
Start by reading up on what's needed. Two good reads are:
Performance Handling for Mopars, by Tom Condran,
Mopar Action Disc Brake Conversion
http://www.moparaction.com/tech/archive/disc-main.html
Even if you don't need to convert to discs (your demon probably has the 4 piston setup), both sources have really good general knowledge. In particular, the Condran book has Moog part #'s and install tips.
That said use these sources as starting points. There's a lot of neat new products that have been introduced since these were written, like greaseable lower control arm spindles. Forums such as these are great resources for learning about new stuff.
