I haven't taken the boys out together by myself yet, but will be very soon. I'm thinking about logistics for loading them in and out of the car.
DS1 doesn't always listen to me when I tell him to do something, so I don't think I can trust him to not dart out into a parking lot when I'm getting DS2 loaded. Because of this I think it might be easier to get DS2 out of the car in his carrier car seat, then bring him over to the other side of the car and set him down next to me while I unload DS1 and walk into wherever we are going by holding DS1's hand and carrying DS2 in the car seat in my other hand. Then to load them back up it would be the same in reverse - set DS2 next to me while I load DS1 and then get DS2 into the car.
What have you found works best for you?
Re: Loading LOs in/out of car
When my kids were small, I always got the carseat out of the car first (it was on my side anyway, so it was most convenient), then got my oldest out of the car.
Now that DS is older, I open the door, let him climb up and get into his seat, and then go buckle my youngest in. I get in the front seat, turn around and buckle up his seat.
I usually do what you're thinking about except that I hate carrying the car seat around so I put the baby in the sling or whatever and then get the toddler out. When we get back to the car I open his door and let him climb in and go put the baby in and come back. If I'm worried about him getting back out I'll close his door while I put the baby in. I do this because I have a hard time buckling him properly while wearing the baby (unbuckling I can do though).
Another strategy that works for me is that my son loves to crawl under the baby's car seat to climb into his seat, so I just open her door and let him climb under while I'm buckling her and then go put him in. That works really well but I think the novelty is part of it so I don't do it every time.
If we're at home, I put him in the car and then get DS2 in the car. Upon destination, DS2 is taken out first and then DS1.
DS1 is getting better at holding my hand, so we are working on him holding my hand while DS2 is in the infant carrier in my other arm.
If I plan on wearing DS2, I will put DS1 in the cart and then put DS2 in the ergo. This is my preferred method for grocery shopping or other stores with carts.
My kids are 25 months apart, but my oldest is a good listener. I open his door and tell him to get in. He does, I close the door. He climbs into his seat while I walk around and put DS2 in. Then I walk back around, open DS1s door and buckle him in.
If my kid didn't listen I would do it exactly how you described.
DD february 2010 | DS october 2011
*please excuse my typos, bumping from my iphone*