Hey Coach; a bit of the same. No question if you limit your shooting distance the 30-30 can get the job done. However, think about the area you plan to hunt, how you plan to hunt it and who you are going to get (if anyone) for a second gun. If you find a good pond (should be lots around this year with all the water!) and the shots you'll have to make are under 200 yards, then I'd go with your 30-30. However, if you, like many of us, end up in a clearcut or a series of them that you plan to drive/scout during the days, I'd suggest you borrow something bigger like a 30-06 that can get the job done well up to 300-400 yards. Whatever gun you take, be sure you go to the range prior to see just exactly what they will do at these distances, then you won't be surprised the day of if you miss, or things don't go as planned.
The biggest fear would be going with and relying on your 30-30, then ending up in a position where you see a big old mossy back that's 300 yards away. If you are a very patient man, you may not have problem, or if your caller is quite skilled at bringing them in close, you may still be OK. However, you gotta remember there are only THREE days. That means that chances are not as plentiful. If you are hunting up north (say zones 2,3,4,5,6,7,8) then you still may be oK because the moose numbers there are high enough you'll get numerous chances. But if you are in the south, and not in zones 15, 20, or 23..... I'd ask a hunting buddy of mine that has a 30-06 to purchase the second licence and IF you end up in a pickle where your moose is a bit farther away, you then have options.
We have tried moosing twice now with archery. The first year, we went with no back-up. We were set up on a small pond, and ideal for a close 20-30 yard shot. However, some raving idiots decided to have a 4-wheel mud bog on our pond (actually no interest in mud bogging, just tormenting us moose hunters) and things with our setup changed in 5 minutes. We had to relocate, and the odds became hugely against us. We actually had to suspend day 2 for a trip BACK out of the woods, gain a new weapon, and then try our luck day 3. Things improved, but our distance from the moose burnt us. A huge 28 poit bull was on his way to my call, but Mr. "Johnny on the spot" shot him on his way to us as he crossed a cut road coming in. easy come, easy go.