This is how I pack our bags. I pack in Sets. I take the Bottom (shorts, jeans, skirt) and fold them at the side seams flat, then put one pair under garment, one pair of socks unfolded, and a matching Top. Then I go to the bottom of the Pants/Shorts/Skirt and start rolling it upward tucking it all inside and lay it all flat down inside the suitcase. I pack 5 sets of clothes, 2 pairs of pj’s, one swimwear, and a jacket for Fall, or Spring for each person, with their personal toiletries (in a bag, or ziplock bag) in their personal suitcase. Since the boys are still small they share a suitcase. One side is for one and the other side is for the other. I also color-code all three. They know their color and I don’t have to mark names on items. (See travel colored toothbrushes in picture) 
I bring along a lot of movies for the road. When and if they get bored we find a Red Box and Rent something new and fresh. 
While driving I dress everyone very comfy. I like to wear Yoga stretchy pants for comfort. No one is going to see us, we’re just driving, lol. 
I bring Olay make-up removal pads (to save the hotel’s wash clothes from my make-up stains), liquid hand soap, TP, Lysol wipes, and a clothes stain stick ( for food and drink spills). It helps us stay clean on the road.
I keep a roll of quarters, laundry soap, and a fold-able laundry hamper in a bag while traveling. If we need clean clothes, I do laundry at the hotel. I’ve been known to wash clothes at hotels (most hotels have a guest washer & dryer) just so I don’t have to do laundry when I get home. And the sets are clean and I keep those sets in the suitcases for the next trip. ( We travel a lot! ) If a set gets a hole, a stain I can not get out, or simply worn out, I go buy another set to replace it.  I bring plastic bags and place in each travel bag/suitcase in case there is a set of clothes that needs to be washed. I keep a stain stick in them to pre-treat the garment so the stain doesn’t set in.