Google has recently cracked down on simple "redirect" landing pages. You could get slapped. Instead, you'd essentially use the "google cash method", and insert your affiliate link into the destination URL of your adgroups. (Adgroups should handle destination in the content network, not ads or keywords)
On the other hand, you might be ok doing a redirect too, you can try both to test and see what Google says. Landing pages are good when you need to improve your quality score, which drives down click cost.
But your CTR on the content network doesnt factor in as much as it does in search, so just create a tightly themed set of adgroups and keywords, make sure your main keyword is in the ad headline. This should help you avoid any "slaps" for lack of content.