Senior Engineering Designer Perry Medina describes a quick way to access various linetype files if you keep them in folders other than AutoCAD's default location.
"The trick is to place a shortcut to your folders or files in the place that AutoCAD looks first. This can save you several clicks when you browse to find them.
"In AutoCAD, in the Layer Properties Manager, click on a linetype. In the Select Linetype dialog box, click Load, then click the File button. You are now looking at the default location for AutoCAD linetypes. Place your shortcut in here. Now, whenever you need to find a linetype, the shortcut will be there to save you from browsing through several levels of folders.
"One way to do this is to browse to the linetype file, right-click, and select Copy. Then you can right-click where you want to place the shortcut and select Paste Shortcut. Alternatively, you can browse to your linetypes folder, and drag the folder to the Places list on the left side of the Open dialog box."
Notes from Cadalyst Tip Patrol: Another method is to put your custom linetype files in the same folder as the default linetype file. There is good reason to keep your linetype files in a location separate from the default. If you have a company network with several CAD workstations, saving your custom linetype file on the server is a good idea. That way there is only one copy of the file, and only one place to go to maintain it. You won’t have to go to every machine and make sure each has the correct file.
I would also suggest that you do not modify the default linetype file that comes with AutoCAD; make your own instead. It will make migrating to the next release a bit easier: you can just take your file with you.