This was sort of discussed in another site, and Indrah included some useful comments in one of her posts:http://forums.rpgmakerweb.com/index.php?/t...ive-easy-steps/
In case you are unable to find her comment, here it is in quotes:
"@Amerk: What's the purpose of those areas and what are their main features? How do you separate the screens?
I'd tell you to first and foremost get a clear idea on WHAT the player does in those areas. Once you have the rough idea, think of how many "filler" or "corridor" areas you want and how you separate and connect the maps, and then do the actual mapping.
For example, the mountain path: If you're only meaning to connect two areas, I'd tell you to use either a winding road with a sky parallax in the background to show ascension and descension, you can use the cliff tiles to show elevation and so on, but I'm aware that on the whole the VX boxy tile style makes mountains on the whole tricky to map. It's a kind of cliche trick to make some maps that go through caves to connect various areas in the mointains, since caves and such are easier to map. If it's merely a road, keep a linear (not straight) path and maybe do a couple of small side roads or alternative channels with a few freebies.
Grasy plains and praeries have the difficulty of no real classic "divides" like thick tree walls of cliffs. If you want to keep the player on a more or less strict path (not a huge empty field) I'd say making a very slight elevation (not a cliff, just a slightly elevated path or an unwalkable terrain) around the road, and if necessary have the characters comments on "Don't go too far from the roads" to give the player some excuse as to why they can't step on that.
On the whole, wide open areas are not recommended, because they're a bitch to map and fill out, and may feel confusing to navigate. If you MUST map big spaces, try to have a clear route (dirt paths, non-grassy lines, guiding stones, etc) and plenty of landmarks so the player doesn't get lost."