left to right = 24".
Front to back = 15" at it's widest. (at wheels)
Floor up = 2".

Fully extended.
Height = 39.5"
Width = 15"
Front ot back carrying area = 9"

Fully extended 39.5".

Expended two sections.
Height 31.75"

Not extended = 24".

No problem with two boat boxes.
Could even get the third box on there.

Where did I get it for less than $25?
Ebay . . Adjustable Luggage Cart.
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Sept 8, 2018, I used this cart for the first time.
Launching was good.
Recovery was good to a point.
I got the boat out of the water and I turned to look where I was going so as not to stumble.
Well, as I turned around, the boat slid off the cart.
This resulted in repairs to the lower rudder, right side planes stab and the right side bow plane.
Worked a couple of hours for 2 days to make knew parts, fit them and then CA them in place.
Touch up paint and the boat is good to go.
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I knew I needed to put some sort of non skid on the cart deck but did not do that before using it.
After repairing the boat, I went to Home Depot and found something that looks like it will do nicely.
  (traffic Master 17"x30" Chevron Door Mat )(1001 535 108)

A door mat that is felt on the top and rubber on the bottom.
I looked at and handled 2 dozen or so mats.
When I got to the one I bought, the top was too soft and slippery but the bottom.
I ran my hand across the rubber bottom and like to have removed skin from my hand.
The size of the mat is 17"x30" which will make three 10" pieces that will fit the cart deck.
 
 
I now have 3 pieces I can use.
I took the mats out to the outside work bench.
Using my 4.5" sander, I lightly sanded the felt side removing all the felt down to the black rubber.
At this point, I brought them inside and using a wooden block and 80 grit sand paper, I sanded any high spots off.
Using air, I blew off the dust from the mat.

     

     

   

  
I then placed the mat on the cart deck to get the measurement between the cart handles.
Using heavy scissors, I cut 2 notches on the long side to fit between the handles.
I make the front of the mat so it was on the deck exposing about 1/8" of the deck past the mat.
 

  
I placed cart on the bench and placed the rubber mat on top of the deck. Rubber side down. 
I moved the rubber so that 1/8" of deck showed past the front edge ot the deck.
I move it all just past the end of the bench edge.
I used a marker to trace the front edge of the deck.
The moved the cart so I could trace one side, then the other.
  
Using a small steel square and exacto knife, I cut the sides of the mat so it was 1/8" short of the cart deck.
I rounded the corners so there where not points.
  
I cleaned the deck and then wire brushed it with a stainless brush to rough it up and give a surface that the silicone glue would get a grip on.
 
I use an air compressor to blow all the dust off the deck and the rubber mat.

I put a large bead of silicone on the deck.
I placed the mat on the deck and moved it a round to spread the silicone until I could see it coming out from under the mat.
 
Place the cart so the mat was on the work bench with the deck on top.
I place two 25 pound shot bags on the deck to hold it down,.
I also needed to put a wooden board between the handles and clamped them in place.

  
Left it over night to cure.