I'd like to stay in china for two months as a tourist, single entry. Is it possible?

Yes, it's possible. You can indicate this point in the blanks right behind item 2.4 to 2.6 on the application form.

That's great, thanks. I've since adjusted my route a bit, and I'd now like to enter twice, three weeks at a time. There will be about 1.5 months between my visits. Is that possible?

Yes, it's possible. You can apply for the double-entry type.

Even if I've never been to PRC before? I understand that for a multiple one, I must've held a Chinese entry permit before. Also, a friend of mine says it's rather a difficult process - is that true?

Daniel, it's more difficult to apply for a double-entry type than a single-entry type, but you still have a chance to get it. As long as you can provide proof that can convince the consular officer of your demand, you will be issued with the double-entry.