How Would You Recommend Handling Content And SEO For Two Sites In The Same Niche?

In episode 162 of Semantic Mastery's weekly Hump Day Hangouts, one viewer asked how to handle SEO and come up with quality content for two sites in the same niche.

The exact question was:

I am merging one local city business lead gen website into another one that reaches
state wide instead of one city. Moving all of its pages, posts, etc.

Statewide site is steadily climbing up and its landing pages are currently is on page 2 for
4-5 diferrent cities. Leads are coming in slowly.

Local site is ranking top 3 for a number of profitable keywords, so I have to be careful
not to mess all that up.

I just find it very hard to come up with quality content for two sites in the same niche.
And see no reason to do SEO “”twice””.

can you recommend best way to do it?
301 redirect?
any plugins?

In SEO Bootcamp Jeffrey (recommend highly. that guy is a monster!) mention Redirection plugin…
Are you familiar with it?