You don't have to use a CAD program to create the board art, can be any computer paint or graphics program, a scan or even picture of 1:1 board art from a book or magazine, or hand drawn if you insist. If you can print it on a laser printer, you can etch it on a board.
I've been doing PCB's at home for a few decades now, some for me and some for clients, mostly prototype stuff but they turn out very well. My first observation would be any board simple enough to do with a resist pen isn't worth the trouble, just put the parts on a prototype board and wire it point to point. Plus, resist pens are mostly wishful thinking, by the time the board soaks long enough to clear the open areas, it's starting to etch the edges and inside the resist areas and they look like crap and will likely eat through any thin traces.
The method I've used most successfully are transfer sheets I get at All Electronics, press-n-peel. Print your board art onto these with a laser printer, run it on top of bare board through a GBC badge laminator, peel off the liner and etch. You might be able to use a clothes iron for the transfer but it will probably take a few tries to get the temperature and pressure right. The laminator makes the art transfer effortless. 12 mil traces are readily done and 8 mil possible if you're careful. "Back in the day" I made my share of boards using glossy magazine paper to laser print the image on and transferred to the board with a clothes iron, then soak the paper off in water. For a quick simple board with minimal investment I would consider this a valid method still.
Ammonium persulfate is the etchant you want to use. Quick, easy, no mess. I use a food container with a secure lid sized for the board I'm etching for a tank. Worlds better than the old school ferric chloride. I recover the dissolved copper out of it by putting some scrap aluminum into the spent bath, then the remainder is safe to dispose of.
Here's a photo of a board I did for a relay coax switch project. I recall I laid that one out using an office draw program. Not bad for homebrew.

Mark K5LXP
Albuquerque, NM