Hi Ken. My work flow has been the same as yours, but since I travel a fair amount I want to decrease the risk of losing my main storage drive while camping and driving.
Understood. I guess the question I would first ask is do you want/need to import into a LR Classic catalog while in the field? If you are primarily culling, then there are a number of options to cull your images before you import. The most popular paid option is Photo Mechanic. Free or low-cost options include FastStone Image Viewer, BreezeBrowser, FastRawViewer to name just a few. if this works for you, then leave your main drive and main catalog at home and do the importing there when you can transfer the images to your primary storage drive.
If you want/need to use LR Classic in the field, then you have a couple of commonly recommended options - bring your primary catalog and Smart Previews with you on a portable drive (but leave your image files at home on your large primary storage drive) or create a travel catalog that you can then export to your main catalog which remains back at home. Each workflow has advantages and disadvantages and only you can decide if either, or a modified version of either, will make sense for you.
The issue with either approach is moving your new files form your travel drive to your primary drive and letting LR Classic know about the move. You can move them in the program, which is pretty straight forward, but possibly slower, or move them outside of LR Classic and then point the program to them after they have been moved. The key to keeping the latter approach simple to to try and keep a similar folder structure so all you are doing is moving a limited number of folders from one drive to another. Files scattered all over the map (for example) that are copied to a new drive all over the place will make this process challenging. I am not saying you are doing the latter, but am using it as an example of when things get difficult.
I have been using LR since it was released in 2007 or 2008, but I tend to do a lot of file management (culling, renaming, backing up files) outside of LR before I import. It jsut works better for me. Others like to do it all inside of LR. It is all a matter of preference and desired workflow.
Hope this helps,
--Ken