OK, I managed to do the first timed Troll Patrol (all the quests were non-violent ones) and did it just in time to get the Congratulations! bonus, which gave me even more XP than wowhead claims (31,750; may vary by level). The next day I couldn't do two of the four subquests, but after doing all the other dailies I went back and discovered I could drop & re-get Troll Patrol and do the dailies again! The subquests don't change, but I can always do at least two of the four subquests, each of which is worth 5300 XP. I mostly did the Alchemist's Apprentice to practice it.
I might skip the fishing daily, because it's worth 0 XP, and I can substitute a Troll Patrol subquest. The subquests are worth the least of my dailies, so I won't drop any others yet. I'll do the fishing daily again when I hit 80.
I'll try to do Troll Patrol last, so I know exactly how many dailies I have left (sometimes I can't do the Shattrath cooking daily, and it's possible I won't be able to get Venture Bay to be Alliance so I can do Riding the Red Rocket). I can discover if I can do all four subquests (a 44.4% chance), and do the subquests until I have 6 dailies left, which should be just enough to do all of Troll Patrol and Congratulations (assuming I can do them fast enough). Of course, if I can't do all four subquests, I can just do some of them over & over until I hit 25 dailies done.
With this additional XP, I should be able to level up faster than one level per week.
UPDATE: It's even better than that, though this might be considered an exploit...
If you abandon Troll Patrol after having done some dailies, those dailies DON'T COUNT once you log off & on. While logged in, they count towards your maximum of 25 per day, but logging recalculates the totals in some way. The upshot is, I can do Troll Patrol subquests as many times as I want. However, each subquest is only worth about 1/15 of an XP bar, so I will probably only do it if I'm close to a new level. Addendum: it seems it's the "duplicate" dailies that don't count, i.e. if you do Alchemist's Apprentice the first time, it counts as a daily, but if you do it a second time, that one won't count if you log out and back in.
UPDATE TWO: Keep in mind that if you can't do the subquests fast enough to get the Congratulations! quest, just DON'T turn in "Troll Patrol" - drop it, (log off & on if you have fewer than 6 daily quest slots remaining), and take Troll Patrol again until you do them within the 20 minute limit.
UPDATE THREE: It appears the random subquests aren't independent; you get one of three random 'sets' of subquests, and luckily, the two quests I want to avoid are in the same set, so I have a 2/3 chance to do all the subquests instead of 4/9...