Maybe everyone has figured this out already but I thought I'd post it here in case someone else finds it useful.
I use both Google adwords and targeted email campaigns. In both cases, I am trying to get someone to click through to a landing page which then tries to get them to follow a links to sign up for a free trial. What I found is that you can use Google's cross-channel conversion tracking to track conversions from email campaigns, i.e., how many people click to the landing page vs. filling out the form.
The tricky thing is, in Google's cross-channel tracking, they have a campaign type=email but that is not what you want to use if you want to track conversions. Instead, set the campaign up as a PPC campaign (sub-type Other) and Google will gove a code snippet for both the landing page and the conversion page. I then use the tracking URL provided by google as the go-to URL in the Sugar campaign configuration.
The email campaign type only tracks click-throughs and not conversions. The tracking also allows you to create different URLs for different keywords. In my case, I use these "keywords' to track results by different campaigns/email templates. Obviously there are a lot of other ways to do this but it's nice to be able to have all your information in one place and let someone else write the code for it.