Actually, I have towed (probably and hour each way) at freeway speed with the bow and cockpit canvas / pole arrangement and had no issue at all. The poles don't even shorten. But then I don't have the canvas surface area of a 240. What I have noticed is that on the 16hr. trip back from NH with my baby, the WakeBoard tower bimini had enough play inside the boot for the bows to rub through the canvas where it folded between them in a couple of spots

Not earth shattering but I had a few tiny daylight spots that will eventually evolve into rips.
Thankfully, my dealer worked his usual magic and asked for a new mid section of the top and they sent me a whole new bimini

- how sweet.
Normally anytime she is on the trailer she gets the trailering cover - towing or parking. It is a lighter synthetic fabric which would be more water proof than the canvas however even with a pole / strap anti-pooling setup (it has rubber foot cups on the pole ends) it really vacuum packs into the bow on the highway. This unfortunatly pulls the sides up over the rub rails to where they can flap in the wind and scuff the shine off the black gell. I will probably have some loops sewn in for straps 1/3 of the way back from the bow to resolve that issue - other than that the cover is easier to throw on than the canvas - more water proof and covers more of the boat. It is really nice - just needs a tweak or two for highway trailering. The boat is always filthy from the rubrail down after towing so I would hate to think what the white interior would like like if it wasn't covered.