I would assume that a dough hook would attach in the same way as the beater does, but the trouble might be in the size/shape.  I think the smallest dough hook is made to fit the K4, which has a 4 quart stainless bowl, but it's a different shape than the 4 quart glass bowl of a 4C. 

It could be difficult to find a hook from a K4 to see if it's compatible with the 4C bowl.   Others here who are familiar with the 4C may be able to advise one way or the other.

I have a K4 with all of the familiar attachments, but it's a totally different animal from a 4C.

I have a 4C and it's intended for average mixing duties, not bread dough.  It was marketed to compete with Sunbeam.  The user guide I have was for both the 4C and the K4 and the sections for each were separate and showed what could and couldn't have the 4C used for. 

Excellent point, Bob!

I love my 4C.  Kelly gave it to me, so it has super sentimental value to me.  I use it for light duty.  He sent me the original glass bowl.  He also sent me a stainless steel compatible 4qt. bowl.  The mixer came with a universal all purpose whip.  He sent me a whip for each bowl.  They aren't fully interchangeable.  My 6 qt. Professional 600 model has an option called the 3 qt. combi lift bowl.  It has a similar universal whip for that 3 qt. bowl. 

I got my K4 from Kelly! 

For most of my baking jobs, I think its bowl is large enough.  I may give it prime real estate in the kitchen of our new house.  It deserves better than being shoved away in a basement cabinet like it is now, and I like the streamlined handle on top for tilting the business portion out of the way.

Ralph, I hope you do.  It will look amazing on the counter in that beautiful kitchen. 

You mean hunting for another 4C, or a whole new/new to you mixer?

If you want to find a 4C, then it sounds like you're S.O.L. with regard to using a dough hook, so that might be a deal-breaker right there.

The K4 takes a specific bowl that mounts differently from the typical KitchenAid, so your best bet for a used one would be to find a K45 or K45SS that was made by Hobart.

If you're not limiting your options to KitchenAid and are considering buying brand new, there are quite a few other makes that offer mixers that use the same basic planetary gear design, but I can't advise on their performance or reliability.

I would cruise the usual on line resources for used stuff.  If you haven't tried shopgoodwill.com, they often have some interesting vintage small appliances listed.

If you google "kitchenaid 4c mixer" you'll likely get a hit on one that's for sale.  It might be 3K miles from you, but then again it might be within striking distance.

One thing you can use on a 4C is any optional attachment that's driven by the hub, like juicer, grater/slicer, meat grinder, grain mill, etc.