Here are two long term views of the Dow. The top chart shows the trend of the market prior to 1995 when its growth rate accelerated. If the market reverts back to the 1982-1995 growth rate and we project from 1995 to now, the chart indicates that a level of 7000-7500 is a reasonable valuation.
The bottom chart is a longer term view and is drawn on a log scale. It shows a price channel for the market from 1967 to now. This channel has held well over time. It is currently sitting at the bottom of the channel.