I'll give you a tip for finding the Audino, because there aren't a lot of good cycling spots on 23.
If you have already visited, Fly to Victory Road. Exit through the gates back to Route 23.
Head south past the Ranger. Here you'll find a cliff to your south that hangs over the area that is hidden behind it in front of you. Go slightly east, then align yourself so that you are hidden behind the tips of the trees. If you are aligned perfectly, you will trigger an Audino (occasionally Gliscor, Throh/Sawk, or the dreaded Emolga) in the single front patch of grass every single time. They are usually between Lv.47-50 and no longer have Secret Power known by this level (no sleeping for you), instead knowing possibly Double Edge (at Lv.50), Take Down, Entrainment, Simple Beam, and Heal Pulse in some combination. (NOTE: If you misalign, you will trigger grass sometimes on the ledge to the left of the lower grass patch but not see it. Line up properly and you will get the right patch every time. Occasionally, it may trigger TOO fast and go to the upper ledge; in this case, just trigger a standard battle and fight - or run away - and then try again.)
If you later seek Lv.55 ones in the post-E4 areas, you will find they have replaced Heal Pulse with Last Resort, but there might be the odd one that still knows Heal Pulse. I tend not to seek out those in Black, sticking to Route 11. Might upgrade before going to the second E4.
Also, I just cycle back and forth in front of the Daycare on Route 3 for Eggs, and I do Egg hatching on Skyarrow Bridge. The latter has over 300 steps and, with Volcarona (or another Flame Armor ability) in the party, makes it seem quick! In White 2, I might occasionally pop into grass to tackle a high-level Audino.
i was leveling up my starmie and i thought that might be quicker but he's past lv 50 now so its good...leveling a skorupi with exp share on marvelous bridge very slowly, but making money with wings while im at it. 70 wings=10500 poke dollars=10 vitamins
I'll have to glance at my Black. Right now, W2 is in my system and I'm training on Route 23 (finally found the perfect Audino hunting place, and they are the rich experience ones Route 11 used to have; even found Sawk there like in the old Pinwheel Forest finding Throh in Black). After a little more, I'll take a break and look.
Downside? Emolga and Gliscor also show up like then.
Just as a note, I already have a 649/649 Pokédex, so there isn't any specific Pokémon I desperately need.
If anything, trying to get a female starter would be a way to go; that way, it helps my breeding when I breed said starter with a male in my possession. I'd have to get back to you on one I need, but I think my Emboar is female so I know that one I don't need.
oh my bad....I've got a bunch of staryu, skorupi, absol, ferrothorn, zangoose, growlithe, a couple unova starters and a couple of scythers i've been breeding if you're interested in any of those...i've also got some of the poke's exclusive to black 2 that i could breed; magby/magmar, buneary/lopunny, heracross, spoink, gothita, mandibuzz and gible.