You may have already followed these or most of these steps, but here they are anyway. Before you change active households:
1. Create a new manual caste.
On City Hall or an in-game computer, NRaas > SP > Caste Options > New Caste (let's call it "Rotations")
2. Open to the new caste in Caste Settings and make sure it is set to Manual -- that is, Caste:Automatic = False, and change Caste:Apply to Household to True.
3. Adjust the settings that you want for the household you are about to leave behind. Here are some settings that I use, but your preferences may vary.
Career: Allow Progression = False (sims will still go to work, but this should take care of and hide most of the other career settings, including Find New Job)
Caste Priority = 5 (just in case your household's sims are in a different caste already, this one will take priority over 0 through 4)
Death: Allow Aging = False
Household: Allow Move as Family = False
Household: Allow Move Solo = False
Money: Allow Inventory Management = False
Personality: Allow Occult Change = False (only relevant if you play with SP Personalities)
Pregnancy: Allow Adoption = False
Pregnancy: Allow Can Be Pregnant = False
Pregnancy: Allow Participation = False (note that if one of your sims to become inactive is already pregnant, you will need to set an exception for them on the Sim level or else SP will terminate the pregnancy)
Push: Allow Skills = False (this is my personal preference, you may not care if these sims pursue skills in your absence)
Romance:Allow = False (they can still have "fun" with their partner, but no new romantic relationships or breakups please)
Skill:Allow = False
Skill:Allow Harvest = True (while not pursuing skills generally, their gardens should not totally fall apart either)
And hit the checkmark twice to accept.
4. Put the household you are rotating out of into the new caste.
Click on the map tag of the household in Map View or anywhere on the ground of the lot, NRaas > SP > Household Options > Caste Manual, and select the new caste you just created.
Checkmark twice to accept. The settings will flow down to all household members, for as long as they remain members of that household.
When you are ready to leave the son's household and return to play the parent's, just before switching take the parent's household out of this caste and put the son's household in. I like to think of it as returning a library book and checking out a new one when I do this.
And finally, about those unwanted career switches. I've never had an inactive dragooned out of their existing job this way, but the game sees unemployed sims as safe to use to fill empty co-worker slots no matter what and SP can be powerless to prevent the game from doing so. If you really want an inactive sim to remain unemployed, you can use MC to change their status to Retired or, if you have the NRaas Careers mod, give them the special "Unemployed" career placeholder (no work hours, no pay, no advancement) and the game should leave them alone.
This all might seem like a lot of work at first, but it's really a one-time setup than can be tweaked/adjusted as you go as well as exported and imported into other worlds/games you might play. It's not totally flawless. But my married, totally committed since they first laid eyes on each other sims have never once strayed away from each other or moved out, etc. with these settings in place. Nor have my fear of commitment totally playing the field sims ever gotten married and settled down when I wasn't looking either -- they can try but SP shuts those actions right down. :)