Rav Yisroel Reisman writes,
In the deeper meaning of Kadeish Ur'chatz it seems to be an inverted
expression. If we pride ourselves in the Seder of this evening then
Kadeish would mean to make yourself holy and Ur'chatz would mean to
wash yourself off of the Tumah that you have. If you want to clean
something you first get rid of the dirt and then you apply the shine.
It should be R'chatz V'Kadeish? We say Kadeish first and Rechitzah
second. That is Seder. People think that to reach levels of Kedusha
that they must rid themselves of the Yeitzer Horas and get rid of all
the things that drag them down. We say on Pesach, no, just jump into
the Kedusha. Even if you feel unworthy and that the Yeitzer Hora is
dragging you down, Kadeish just jump into the Kedushah. Why? That is
what happened on Pesach. Klal Yisrael still in the Mem Tes Sharei
Tumah just jumped into Kedushah. There was no big Teshuvah movement at
the time. We see this from the Yam Suf where it is said Halalu Ovdei
Avoda Zorah V'halalu Ovdei Avoda Zorah. We know that a Shifcha at
the Yam Suf saw more of a prophecy than Yechezkel Ben Buzi. By
Pesach we tell people do what your forefathers did, just jump into the
Kedushah. After you jump into the Kedushah you can worry about
Ur'chatz the getting rid of your Yeitzer Horas.
Rav Reisman seems to be saying the vav in Ur'chatz is connecting it directly with Kadesh. Specifically say Kadesh without getting rid of the things which can drag a person down. Then after jumping into the Kedusha (Kadesh) you can work through Ur'chatz.