Yes, Changde (CGD) could be an option, I think China Southern flies an afternoon flight Mon, Wed, Fri, Sun. It would save some road time vs. Changsha. But I think still not that cheap (over RMB 1000 all-in--and if I wanted to avoid the bus trip entirely, I'd just suck it up and book a flight from ZJJ at that sort of price magnitude. The main reason I don't like to recommend these limited non-daily small airports, is that in case of cancellation, you have no reserve option. The only means of recovery would be to spend the night in Changde, carry on to Changsha the next morning, then try find a fallback space on train or plane to get to Beijing. Less of a problem if you have schedule flexibility, but you don't want to cut it close if you've got that international flight out of Beijing looming. From Changsha there are many "escape routes" to get back to Beijing in timely fashion. My personal strategy, if budget/money was an issue, would be schedule out of there, Z or T train if I could get a ticket, plane if I couldn't. And reserve in advance for peace of mind.