Well, first things first:
This is incorrect. Seeds do have a measurable amount of THC. In fact, the DEA once seized 17 truckloads of hempseed at the Canadian border because they contained THC. Of course, it’s totally legal to import THC-containing seeds for use in birdseed (in fact, birdseed was specifically mentioned in the original law banning pot), but that didn’t stop the DEA.
I will, however, agree with you that the stems and seeds make for a very harsh smoke. I usually dump mine down the garbage disposal.
How to smoke pot without coughing
Of course, the easiest way is to take very small tokes. The bigger the hit, the greater the likelihood you’re going to cough up a lung.
Another way, which most people have never heard of, is to vaporize the pot. This involves heating pot to the point of THC vaporization, but not to full combustion. The vapors have sort of a piney taste and are not as likely to make you cough since you’re inhaling no smoke. Any head shop, online or IRL, will be able to sell you a vaporizer. Prices range from $30-$400.
Eating
I really don’t recommend this. It doesn’t really produce too much of an effect on me even though I’d use doses that were several times what I’d normally smoke. However, some people swear by it and say it’s simply wonderful. YMMV.
The main reason I don’t like eating pot, though, is that it simply tastes vile! I’ve made pot brownies, cookies, and a pot/vodka solution. Each time, I had to try my damnedest to choke the stuff down without throwing up.
Medical pot in CA
I think you can get a special “pot card” to show any policeman who might be harrassing you. I’m sure that’s how they do it in Oregon, but I’m not positive that that’s how it’s done in California.
As far as obtaining medical marijuana, I think the laws allow for a certain number of plants - it’s 7 in Oregon. If you don’t want to grow it, cannabis clubs may be able to help you out by selling it at costs far below what you’d pay on the street. Check out http://www.marijuana.org for California-specific information on medical marijuana.