i don't know what kind of options you are talking about. I will assume that the options are like big shower vs shower & tub & or bay window etc... There are times where a save as is quicker and requires much less setup on the front end. You could always keep updating a base version and if the alternate option is chosen, you could delete the area in question and paste in the option from the other drawing using "hold position". Of course, nobody wants to update more than one version simultaneously. I don't recommend this, but it simpler in some cases. However, I would recommend learning to work with building options as much as possible since you mentioned plan sets. Its much more adaptable in plan sets.
You could put your option area into a selection set and assign it to an option, other than default. I would setup the option name as well. Most important part, put the area that the option will replace into a "Standard or Base option name" building option as well and take it off of default. Even the standard portion will become an option. If you wish you could put this on a radio button which is a new feature that automatically cancels out the other version, like a toggle switch. This works even better for when you have a few options or you are managing a master plan that will be built on multiple lots with clients selecting options.
Best part is that you could show all the options on the plan set by dragging in the plan multiple times and assigning a different option each time then cropping. We were never able to do this on the same sheet with multidrawings.
Its not that complicated after you do it a couple times. One of the best ways to practice is to use an optional kitchen island, then a upgraded kitchen island. Attach dimension on both while in each building option to assure the notes and dims are complete.. It takes diligence. Softplan is the best program at handling options right out of the box.
But if you don't want to manage options at that level because you are just going through conceptual designs, you could definitely saveas or even a layer. Always more than 1 way.