From what location would you advise Ukraine attack from?
I have thought, however, how satisfying it would be to put some ordinance in the middle of Moscow to bring the point home to Putin. It woke up the Japanese to bomb Tokyo from an aircraft carrier early on in WWII. Militarily it didn't amount to much, but Psychologically it put the war in context to the people in Japan. If a few claymore mines went off in Moscow, especially close to the Kremlin, maybe a general would figure out Putin may have made a mistake.
Do Russians really think they will casually sit in a Starbucks in Ukraine 6 months from now and not expect a grenade tossed in the front door? Ukrainians will strike back on "Russian" territory eventually.