Have you ever...

...created a map so big and with so many events that it starts to lag when you test it?

I have. 

I wanted my game to be full of huge, rich environments without interruptions (ie. without a teleport event from one part of the city to the next), but whenever I test it...things doesn't move very well.

I guess that's not as big of a problem for an rpg as it would be, say for a FPS...but still, it reduces the realism of gameplay.  :'(

I had the same problem once.  Hopefully you can understand my solution, and I won't babble like an idiot.

Usually when you make an event to teleport you to another map it's on the edge of the screen, right?  well, insted, put the teleport event like 10 tiles away from the edge of the map, and use the instant animation for the teleportation (not like vertical blinds or anything.  In the map you teleport to you be like 10 tiles into the map (the purpose is to get overlap).  When the character steps on the event, they'll appear to just keep moving with hopefully little lag. You coukd cut and paste and split your big map ino like 4 little maps that way, you just have to draw with that bit of overlap, to make it look like the edge of the map isn't the edge.

that's a mouthful

Hm...I hadn't thought of that. That might solve the problem, actually, but maybe I should explain why this map is so cumbersome.

 See, I wanted to make this game a bit more realistic in terms of physics. In order to create a sense of a 3 dimensional world, I made all roof tiles (and even some wall tiles) above hero rather than simply impassable. It adds several more dimensions to the city, since the hero can walk around the structure in four directions, and it appears more realistic. The thing is, though, in order to keep the player from simply walking under the entire building, I surround a portion of the roofs with impassable events. And this is a huge city, so that means quite a few impassable events. 

 How do you format your cities? Do you usually just keep the roofs at the same level as the hero?

Go find an anti-lag script.

I usually make my maps so that they 30x27 so it doesn't lag too much. I just connect one map to another if i want to make a big field. i find big maps can get confusing and too laggy

You could use an invisible impassable autotile  

...created a map so big and with so many events that it starts to lag when you test it?

I have. 

I wanted my game to be full of huge, rich environments without interruptions (ie. without a teleport event from one part of the city to the next), but whenever I test it...things doesn't move very well.

I guess that's not as big of a problem for an rpg as it would be, say for a FPS...but still, it reduces the realism of gameplay.  :'(

Wow, you must've uploade a whole lotta crap on there. =D

Those are good ideas, if the choice were up to me, I'd go with the no animaion teleport. : )

Go find an anti-lag script.

I know i'm killing myself by saying this, but...im a newbie to scripts.

Where can you find an anti-lag script? Or is there a tutorial on that already?

There should be one in the database. I'm not sure who made it but I believe Blizzard spiced it up a bit so it works better.

EDIT: I found one but it wasn't the one Blizzard spiced up so it probably has some bugs. http://rmrk.net/index.php/topic,1924.msg70480.html#msg70480

Wow, you must've uploade a whole lotta crap on there. =D

If this gives you some idea, you can only see about two thirds of the map on 1/8 zoom. 

could you just make them looping map?

I have tried it myself, but I did on purpose. (Well... I had 10-20 thousand events on 1 map >_>)

You can find Blizzard's anti-lag script (ABSEAL) here: http://rmrk.net/index.php/topic,8907.0.html
This might help a little, just know that it will come with some restrictions. A sacrifice you could say.
Hopefully you won't notice what's missing

That was probably not a good idea.

I try to keep mine small-ish...though I haven't begun to create cities, i'm just creating one building area's at the moment...

Thus perhaps if you created area's next to each other and divided up your city, so you wasn't jumping from one end to other but rather just to the next sector.