On the Characters being left behind thing I'd suggest you have one of your other characters (preferably one with mining/herbing) take the lead with your pally on follow. This way you get the benefit of crusader aura but if your leader gets to far ahead the followers keep the speed aura while the leader loses it till the minions catch up... Setting this up can be pretty easy with making your follow macro have the code /follow [mounted] CharacterX; PallyCharacter

On the epic flyers bit, 5 Epic Flyers is absolutely awesome especially when you can turn em into an armada of netherdrakes swooping down on some would be gankers, spend the gold and don't look back. Couple of tricks I've found for getting there...
  • If you haven't gotten to 70 yet avoid questing in Netherstorm, Blades Edge, and Shadowmoon the XP they give is nice but getting 12g for each kill quest as soon as you hit 70 is much nicer. Huge boost to your initial gold when your gear isn't quite up to snuff for heroic instancing and such
  • Store all your money on a bank toon or a personal guild bank, keeping only 50g on each of your characters. If you don't have money to spend your far less likely to spend it
  • Have a Fire Sale from your bank mules, sell everything that isn't immediately useful tradeskill mats included. After your epic mounted and your gear is enchanted you can still make a shit ton of gold with simple dailys so it will be easy to buy stuff you truly need after you have the mounts. This works best if you start it before your guys hit 70 as you can sell it over time instead of having to do a mad rush...
  • If you have friends or guildees you can borrow gold from when you hit 70 to cross the epic flyer boundary, do it (especially if you avoided questing in NS, BE and SMV). You can do dailys and kill quests much faster if you have the epic flyers and pay them back in a couple of days if you work at it. Also saves you 500g from having to buy the regular flying mounts 100g x5 toons. I wouldn't do this if you don't believe you can pay them back quickly, outstanding loans erode friendships quite quickly if not paid back...