I have some problem with the volcano part. If I recall correctly, they were led thru the wilderness by the pillar of smoke by day and fire by night for 40 years. That seems a bit long for one volcano to spew.
Volcanos can spew ash for long periods and appear fiery by night.
Mauna Loa? in Hawaii has been erupting for years.
Still, I agree that scientific discussion of religious text is problematic at best, though fun for some.
Exodus 40:34-38 (KJV)
34 Then a cloud covered the tent of the congregation, and the glory of the LORD filled the tabernacle.
35 And Moses was not able to enter into the tent of the congregation, because the cloud abode thereon, and the glory of the LORD filled the tabernacle.
36 And when the cloud was taken up from over the tabernacle, the children of Israel went onward in all their journeys:
37 But if the cloud were not taken up, then they journeyed not till the day that it was taken up.
38 For the cloud of the LORD was upon the tabernacle by day, and fire was on it by night, in the sight of all the house of Israel, throughout all their journeys.
As you can see; they did not travel continuously, but only if the cloud was 'not taken up from the Tabernacle'.
That is even harder to explain via a volcano...or a comet.