First, make sure the area is completely flat or you will have no end of troubles.
While in path creation, there is a button for "select grid" .
Lay down the first path (what ever width you want but only 1 long). Next hit select grid and then click on the path you just put down. Now turn on Square edges (just below select grid button). Now you can layout a complete path way on the grid just like you could in RTC2. When you are done, just close the window or click "deselect grid".
Couple of helpful tricks with this....you can select building grid items and that will always go to 4m wide path. But if you want larger, just lay down the initial path at the grid you want.....I will use 8m typically and lay out my plaza leaving room for buildings which will fit nicely within 8M grid.
Play a bit in sandbox as things can get a little finicky, but it's significantly improved from earlier days. Hope this helps. Good luck.
Edit: Here's a link to a quick demo I just made on youtube: