Try using the sysvar MAXACTVP (MAXimum ACTive ViewPorts)
Setting the variable to a low number (the lowest is 2) will turn all the Viewports "off" (note the quotes) except for one.
Here are the cool features:
1. When you turn a Viewport ON, one of the other Viewports will automatically turn "off"
2. Even though many of the Viewports look "off", they are actually on and you can still plot the drawing.
3. You can set MAXACTVP from Modelspace. Set it to a low value before switching to Paperspace to prevent slow regens and crashes.
4. If you need to see more than one Viewport on at a time, simply increase the value of MAXACTVP (3 will display two viewports, 4 will display 3 viewports, etc)
Other tricks for quick Viewport regens...
1. Any layers which you do not "see" within a Viewport, make sure they are forzen within that Viewport anyway because layers turned ON will still regenerate even though you don't see the objects within the Viewports.
2. If you have a nu,ber of XREFs attached, make sure they are Attached on their own layer (eg. XREF-Base, XREF-Title-block etc), and then following the above example and freeze the XREF layer within a Viewport if none of the XREF is visible within that Viewport
Hopw these tips help!