Have you checked out the math for calculating speeds and feeds? 2000RPM and 6IPM is way too slow, that's only 0.001 in/tooth. Way too low for a 1/4" end mill.
Spindle Speed is roughly the surface speed (in feet/min) * 4 divided by cutter diameter. Carbide in aluminum numbers can exceed 1000 SFPM, so you can run up to at least 16,000 RPM with a 1/4" cutter. You can run slower with no ill effects here, might want to check out where the peak torque or efficiency is on your router.
Feed rate is the chip load * #teeth * spindle speed. Here's the link to the Onsrud specs. They don't provide a SFPM rating which is odd, they just list 16,000 RPM.
http://www.onsrud.com/files/pdf/2012...20Aluminum.pdf
They list 0.003-0.006 in/tooth for 1/4", you don't want to have this drop too low or the cutter will just be rubbing as opposed to taking a clean chip. Plugging those in gives you 16,000 RPM and between 48 inches/min and 96 inches/min as your feed. If your machine is unhappy accelerating that fast - just drop the spindle down to 8,000 RPM and feed between 24 in/min and 48 in/min.
I like the calculators at this site - they have one for HP/Torque requirements also that will let you get a feel for how heavy your cuts are.
http://www.custompartnet.com/calcula...speed-and-feed
G-Wizard is another nice (pay) piece of software that gives some good suggestions and does fancier stuff like calculating tool deflection on smaller cutters.
http://www.cnccookbook.com/CCGWizard.html
We use KoolMist 77 as flood for our mill (McM 11365K61), but it obviously works as mist as well. It's probably not the ideal coolant for aluminum, but it's one of the safer ones to work with. The MSDS sheet is pretty tame, it doesn't go rancid in the tank, water soluble, no skin reactions, biodegradable, etc.
I would just take the dust-shoe off when you're cutting aluminum, it'll get in the way of the coolant system and you won't be able to see the cut. Bump up the pressure in the mister so that it clears chips from the slot, or mount up an air blast. A lot of milling in steel and hard alloys is now done without coolant, just a heavy air blast to clear chips and prevent recutting. Aluminum needs the lubrication though.