As far as resets, you could even say something along the lines of "looks like the train should be here soon I'm going to go XYZ (lay down for a minute, back to my house, ect.) and then I'll hop onboard" and as a follow up if you want to continue RP with someone and need to see what server they'll be on, "Do you know what stop you'll be getting off at?"
For mechanics, it's pretty easy to just say "You know, people have been asked that question so frequently, they even wrote a little book about it." If they still can't figure it out, you may just have to get creative. Most of the time, so long as people understand the / commands, if you say something like "you may need to see if you can fix your horse, maybe check his hooves to see if there's some mud stuck in there". Emphasizing the appropriate words should offer enough of a hint.
For the 'G' menu... "Gee, have you tried to just lean on that railing."
Keys: "Just alternate the key to the left... you may have to hold it in the lock for a second."
I've seen so many unique and creative ways of explaining all of these things. You can even get ideas on how to explain them to others IC. "I had someone asking me how to unlock a door the other day and they just didn't understand. I told them XYZ. Do you know of a better way to explain it?" Most people are pretty good at working around the inability to go OOC.