From my experience, farming stones in the wild is kind of a hit or miss proposition. You're much more likely to get stones from bags, unfortunately, the bag stones are random, so you could keep getting undead stones (for example).
Unless you have exceptional luck, you won't be getting anywhere near the amount of stones you get for doing the bag dailies. Based on my experience, I'd call the 1 stone every 3 hours (double the bag time investment) to be optimistic as well. YMMV
As the other poster mentioned, you can do trades with other peeps via the trading forum here.
I also found that peeps who weren't that into pets would sell you stones as well if you ask in trade. Then again, you may not have a ton of gold to be able to just buy them outright, I was also probably paying more than they were worth too.
Of course, this only works for tradeable pets, but that's fewer stones you have to find.
I'd say keep doing the dailies and look for stone trades when you can. If you need specific types, by all means farm for them if you have the play time.