Map Loading Time

I'm about to undertake a fairly substantial RPG map. Having never actually comprised my ideas into a map before, I know little about reducing load times. Any suggestions?

There are 2 main factors that contribute to long load times.

1) Triggers firing at map initialization
2) Pre-Placed units.

So to reduce it, make the map init triggers fire at Elapsed Game Time 0.00, and create as many of the units as you can through triggers instead of pre-placing them.

There's a third factor that I can personally attest to, and that's large numbers of abilities, or abilities with large numbers of levels. Since each level of an ability counts as its own ability, pretty much, those two mean the same thing.

I can't really tell you how much is too much, but I had a map with 24 heroes, each which had four 10-level abilities and one 3-level ability, and the map took over two and a half minutes to load, with almost nothing else in the map.