Found this in ref: to the 2018 Highlander (sorry don't own one to measure) If 2nd and/or 3rd row are the cargo area loos like they'd fit?. I'm using the Hip Measurement as a guide. Not sure if every year were the same so you may just what to tolerate a sales rep long enough to take some real measurements for yourself since you know exactly what your dealing with. Good luck!

Toyota Highlander Specs - Exterior and Interior Dimensions

Body 4dr SUV Wheelbase 109.8 in Length 192.5 in Width 75.8 in Height 68.1 in Curb Weight 4165 lb. Fuel Capacity 19.2 gal. Headroom, Row 1 40.7 in Shoulder Room, Row 1 59.3 in Hip Room, Row 1 57.2 in Legroom, Row 1 44.2 in Headroom, Row 2 39.9 in Shoulder Room, Row 2 59.6 in Hip Room, Row 2 57.1 in Legroom, Row 2 38.4 in Headroom, Row 3 35.9 in Shoulder Room, Row 3 55.0 in Hip Room, Row 3 45.6 in Legroom, Row 3 27.7 in Total Legroom 110.3 in (over 3 rows) Cargo Volume, Minimum 13.8 ft3 Cargo Volume, Behind R2 42.3 ft3 Cargo Volume, Maximum 83.7 ft3

 

46” between wheel wells and rear door open height is 31”

 

Thank you both ! 46” would work, but would be super tight. Was it slightly below 46” or slightly above ? (Or exact?)

I ruled out the Honda Pilot, since it is only 45.5” between

 

My 2018 Highlander measures closer to 45.5 at the floor. You'd also need to consider the depth since the ceiling gets lower as you approach the tailgate and the crates may not fit all the way back. Depending on your rear seat configuration they may need to be folded down. Best bet is to do what I did with my golf clubs. Take them to the dealership and see how they fit.