I definitely recommend going- I agree with the rest, you'll need to spend at least 3 hours, no more than 4, to check everything out. I live only 15min from the meet, so I'm pretty familiar with the area. Here are some other places worth checking out:
- Weil Antique Center: About 15 minutes from the ATMA meet. Has 3 small sections of quality prewar and postwar trains. Also has a bunch of other neat tin toys. It's pricey, but worth checking out
- Merchant's square: Would've recommended it in the past, now not so much. The remaining major train dealer has gone to another antique mall. The Model Train exhibit and associated shop are only open from the end of November to Late January(despite what the website says). KD Smith auctions, which used to be a great Dutch auction, has moved the majority of their items online and there's barely anything to see there anymore. I might go there tomorrow for the model train exhibit, if I do, I'll report back on the status
- Tony's hobby shop: About 25 minutes from the meet, it's a smaller hobby shop but it's been around for 75 years!! Has a small but decent selection of postwar trains and modern traditional trains, another small but decent selection of modern rolling stock(mainly Lehigh valley road names), and a combo of about 20+ modern and postwar locos. Good selection of fastrack, o scale accessories- people, buildings, scenery- as well as light bulbs.
- Trains & Lanes: I am somewhat loathe to recommend them. If you don't know them, don't expect great customer service. Depending on what you're looking for, they're generally pricey- but you'll definitely find things you aren't gonna find at other hobby shops.
- They have a HUGE selection of modern motive power- Lionel, MTH, Atlas, some Weaver and some K-line.
- HUGE selection of Lionel rolling stock including the most recently released stuff and items from the 80s, 90s, 2000s.
- They have a good-sized selection of MTH premier, Railking and K-line Rolling stock. And a slightly smaller bit of Atlas rolling stock
- They also have a bunch of modern Lionel and MTH accessories including but not limited to: buildings/houses, extra floors for buildings(MTH), operating accessories, replacement trucks, people packs, industrial structures such as elevated oil tanks, coaling stations, trackside structures such as station platforms, signals, scrap yard, barrel sheds, etc... Also have a smaller but decent amount of Woodland scenics ready-built buildings.
- HUGE selection of o scale figures
- HUGE selection of Lionel Fastrack straights, curves, switches, wyes, etc...BIG selection of Atlas O track and still have a decent selection of MTH realtrax.
- Decent amount of Lionel Legacy, TMCC accessories
- MAJORLY HUGE selection of modeler's tools, adhesives and paint(Tamiya, TEstors, Vallejo)
- HUGE selection of Plastruct and JTT sheets, Plastruct beams/bars. Woodland scenics grass, trees, etc..
That's just off the top of my head and only train related places, but hopefully its helpful