where best to spend $2-3000 upgrade dollars in my system

Sounds like a good plan, I commend you for it ;-)
When you are ready for tube phono preamp, and there are many good ones available be sure to take a look at the Allnic H-1201 tube phono amp.

Good plan! If considering dedicated lines into room you might try plugging your amps and preamp directly into outlet, bypassing power conditioner. Use power conditioner for digital gear. Results vary depending on quality of power coming to house. I would also be inclined to consider the new preamp prior to cable changes. 

If you haven't already:
1)Furutech NCF wall outlet.Regardless of the level of your system, lowering the floor noise by using this- considered one of the best- outlets will improve the sound2) Upgrade the fuses in your components. Any after market fuse will sound better. I've tried a lot and the Synergistic Research Blue fuses are by far the best I've tried.3) Better Interconnects. I'm using high fidelity Ultimates now. Very pricey but easily the most profound improvement i've ever made. Their entry level Reveals at $700/meter are suppose to be fabulous for the money.4) Better power cords with quality plugs.5)Some   Noise Harvesters from PS Audio and,  in general, any tweaks or upgrades that's going to lower floor noise.Less floor noise, more inner detail is revealed, the more dimensional  and realistic will be the sound stage.6) MC-0.5 from High Fidelity will improve the quality of the AC feeding your system. Better bass, more effortless sound, lower floor noise.
7) Try some HFTs from Synergistic Research on your walls to improve the acousticshope these tips help. happy listening.

Do not agree that your speakers are your limiting components, they are and asset.