Dread,
I usually don't like posting settings or giving out "helpful hints" without knowing as much as possible about your set-up but in this case i'll try to help you out a bit.
The file that you want to have is a utility called Fs9Configurator by Ken Salter.
Do a search under Fs2004 utilities for the name Ken Salter and you'll find it.
Once you have it installed in the default location than start it.
In order to reset it you will need to right click on the parameter that you want to change and than choose change key.
Insert the change that you want and save.
There are different settings within the .cfg file that control the way textures load.
This is what your .cfg file looks like when you have run the utility that comes with Megascenery. If yours doesn't look exactly like this than it should. You will notice that in this shot terrain extended textures are turned off as they would be with photoreal scenery but not with other sceneries

There is a connection between PAN_RATE in controls and Texture_Bandwidth_Mult in display. Try to find a balance between the numbers. What you see here is the perfect balance for my machine and may not be the best for you.
Pan_Rate should not be more than 900 and Texture _ Bandwidth_Mult should be adjusted in increments of 60 and should not exceed 400

When these two elements are balanced you should achieve a faster load of the tiles but be aware that the settings within Texture_Bandwidth_Mult will affect your FPS.
Megascenery No Cal loads a great deal faster than So Cal
Turn off AA within the sim.
Try to find a balance in your video card which you should generally speaking have at 4x AA and 8x anisotropic filtering for ATI and 2x and 4x for older Nvidia cards.
Vertical sync should be set to application preference.
This of course depends a great deal on the card and the drivers but these are good general rules.
Install a full registered version of FSUIPC because when you have turned off extended terrain you will want to adjust sight distance so that you can control the blurries.