There are definitely a network of buses that travel all over that specific region. Do you mean Moreno Glacier? I think so.... from my experience bus transportation around SA is pretty good and affordable too. You should be able to get from A to B no problem. Puerto Natales is the closest city to the park, about 3 hours drive. You should be able to arrange a bus easily from the glaciers to TDP. It's a very commonly traveled route.
"The main pickup and drop-off points in the park are at Laguna Amarga, the Hielos Patagónicos catamaran launch at Pudeto and at the park headquarters. You can coordinate your drop off in the park with the catamaran schedule, which leaves Pudeto for Lago Pehoé (one-way/round-trip per person US$18/32) at 9:30am, noon and 6pm December to mid-March, noon and 6pm in late March and November, and at noon only in September, October and April. Another launch plies Lago Grey between Hostería Lago Grey and Refugio Lago Grey (US$30 one-way, 1½ to two hours), a couple of times daily; contact the hostería for the current schedule.
are a few reviews of the park from TripAdvisor.
Torres del Paine is huge and depending on what type of traveler you are, you might benefit from a tour. I think if you're exploring on your own you need to pin point what you want to see and do and make a pretty good plan before you head out.
If I had the time, I would personally explore on my own via hiking and camping. I'd get a good guide to hiking/walking Torres Del Paine and take some essential camping gear (I would be surprised if you can't rent some basic gear in or near the park, or take your own) Apparently the best parts of TDP are accessed by foot, but you can also cycle around the park, which sounds pretty awesome.