I'm inclined to say SCUMMVM
as well, although please note, the latest version is being released part by part, as they programme it.
You could get the older one, its pretty much the same.
But be warned. Its notoriously hard to set up. Thats what put me off. (TANDY-SOUND CHIP??? WE DON'T NEED NO FREAKIN' SOUND CHIP!!!!!Oh wait, we do. Thats why I'm stuck with internal PC sound for Maniac Mansion)
Or, more simply, you could make a boot disc, which loads only the required game files.
Theres this program you can download called TURBO, which slows down your computer.( Sorry, I don't have a link)
Try over at IndyJones.Net. That editing forum.... they're real boffins. They should be able to sort you out.