They reset midnight on Wednesday. Use the clan chat world60pengs in world 60 to help you locate them. Do the penguin hunting minigame every week. You can get Quests. You also can buy Runescape Gold service on our site when you do not have time to farm gold.
These can provide loads of experience; the major ones are wolf whistle, Spirit of summer, summers end, and one small favor. The big one is one small favor as that gets you 20K (two 10k exp lamps) in summoning.
Main charm collecting method, loot sharing. You can loot share charms. You are correct when you say rock lobsters are the best ones to loot share, get someone to ice burst you (pay them) or have a rich friend do it. When you are a lower level (runescape money) and can not safely get there then good loot share monsters are Cockroach soldiers, Dust devils and Fire giants.
You can always run scrolls or use scrolls meaning you make or use summoning scrolls; however these are very bad exp but can be fantastic money if done correctly. Right those are the main training methods, to recap, do penguins every week, we cannot stress this enough. Loot share for the majority of your charms/exp in Runescape.