The streetbuilder mod lets you set up a number of points designated as a road, configure the parameters like what nodes and dimensions to use, and goes and builds it for you. That chat command interface is quite workable for anyone used to using advanced commands like, say, WorldEdit. Keeping the README file handy is handy.
The street will build out in one fell swoop when you are ready for it to. It can cut through terrain, which is handy but potentially dangerous at the same time (and irreversible). It can also place bridge piers underneath it. The mod applies a spline curve easing between the points of the road, which is quite helpful and much better than a simple straight line. It will also emerge (load) any unloaded areas on the road while it is building, so you can trust it with making long distance roads and highways. Doing those longer roads may cause the server to lag for some time as it's not done as a background job or spaced out over time in chunks.
My main complaints with the mod are mostly with pushing the limits. It generally behaves quite well.
I can't seem to build a path without a border node, only one with air cut out of the sides. This is particularly bad for 1-node-wide lanes.
The pier nodes always seem to be placed at least 3 nodes under the street, even when it's above solid ground. This is debatable, but should probably be configurable.
The setting for the pier node uses the word "piersnode". I'll forgive the author for being not a native speaker (as best I know).
Setting a new pier node and re-building the road will only replace the old piers up to 3 nodes deep. Of course, this could cause problems with e.g. stone piers, but that is an adversarial case. In general you want to replace the old pier node.