Exploring my interest in building a router table is how I ended up getting hooked on this forum!
As far as hole mounting goes, I have used the plastic sub base on the router as a template when making custom plates. I just marked the holes and drill them out.
It took me better than three days to read through Old Chipper's thread on router tables here. It was worth every minute of it!
What I found by looking at the pictures and descriptions of other user's router tables was examples of most of the different types of custom built and factory made setups.
Here is a link to it: wanted-pictures-your-router-table
6 months and change have passed since I arrived here and I still haven't finished designing that 'custom router table yet'. I put building it on hold and picked up some used routers and router tables from Craig's list to use until it is built and to help build it. Learning before jumping saved me a lot of time and frustration.
I don't really know the details on what other ideas you have in mind to transform this piece of acrylic into a router table, so I will just bring up some design ideas that are just my opinion on some factors. Some people here do just grab a router and bolt it to what ever is flat and handy, flip it back over and start routing!
If that's all it takes to make the crafter happy and give them the results they are after, there isn't anything wrong with that approach at all. I found out that for my needs, a table that simple just wasn't going to cut it as my "only" router table.
Tables where the router is mounted beneath and directly to a single piece top are quick, easy and inexpensive to build. That being said, they are very inflexible many ways. For entry level applications they work just fine, but all to quickly become the number one obstacle when pursuing more advanced routing applications.
In the best quality tables, IMHO, the router is mounted to a plate. The router is lowered through a recessed rectangular opening in the table top sized to hold the plate with it's top flush with the rest of the table top. When I first got here, I thought the thing with 'plates' was all about pre-drilled holes that line up with a particular brand router. I was way off base on that one. The benefits of top-in plate mounting are numerous, but beyond the scope of this post.
A third, middle of the road option is where the plate is mounted to the table top from below. 2 of my three tables use this method. The third uses a single piece top. The table I still want to build (someday!) will use a plate that lowers in from the top.
There are a lot of considerations beyond just mounting it that go into setting up a table mounted router. A fence to guide the workpiece across is in my opinion the 'least optional'. A fence could be as simple as a 2x4 board with a 'cut out' for the back side of the bit. It's primary purpose is as a straight edge to guide the workpiece along as it passes over the spinning bit.
Three fairly important functions that tend to interact with fences are:
1. Bit Guards
2. Feather Board Mounting (helps keep the workpiece pinned to the surface)
3. Dust Collection exhaust port (you can hook a vac hose up to it)
Well that about covers my four and a half cent's worth on the topic...