Commerce/Nexus Subscription

Has anyone been able to tie in Commerce more seamlessly from their main site?  I have paid subscriptions on my forum and a landing page on the main part of my site.  I want to be able for the end user to add to cart from my landing page, I find it a mess to have them go through so many clicks: add to cart, continue to register, checkout and then they have to click on "Continue as a new member", including my lander button, that is 5 steps!  I want to cut it down to 1 step, subscription listed on the top(what they are paying for) & the check out form on the bottom. Has anyone done something similar?

If you are wondering why not just send them direct, because IPS although is a great forum it lacks major as a marketing tool, so I use a landing page.

Any help?