Removing Ridges and/or Router Bit Suggestion

Since these questions may be linked, I decided to make them a 2-for-1 topic.

Anyway, since I don’t currently have a planer, I built a planing jig for my router that is a lot like this one, except my router is screwed onto a double layer of metal strips instead of using metal rods:

http://www.woodzone.com/tips/planerjig.htm

To my surprise, this method actually seems to work fairly well. I move the router side to side over the board in a “cross cutting” fashion, instead of taking long passes from bottom to top, since it is easier to control that way. The problem is that this leaves a bunch of ridges on the board.

I have been sanding it by hand with 100 grit paper in a sanding block and then finishing up with a card scraper. This has made things flat and smooth, but no matter how hard or long I seem to sand the board, I can never quite get rid of some of the streaks or lines that are left-over from where the ridges used to be. This is with hard maple, if that matters.

So, I’m wondering if I need to just keep on sanding, or if I actually need something like a palm or random orbital sander to get the job done here. Or am I just stuck with these streaks?

Alternatively, is there a router bit that won’t leave these ridges? I’ve been using the straight bit that was included with my Triton router for this.

Thanks much for any insights.