I would say the measurment you need is 46.5 which was listed as the width, the track is often measured center of tire to center of tire, the width would be outside to outside.
Never heard of that tiller brand. And shipping rates totally depend on weight, size and distance, it also depends on if you ship to a terminal, a residence (highest cost) or a business with a freight dock (lower cost). So I would expect that you'd pay far less shipping buying from someone west of the Rocky Mtns than you would from someone east of the Mississippi river on a similar size/weight item. I paid $1050 for a Land Pride RTA1550 (50" with side shift) plus about $200 for shipping a few months ago. Shipping was to a business with a freight dock, distance was North Carolina to the Chicago area.