New Website Look/Structure - Should I Redirect or Update Pages w/ Quality Inbound Links

[Southbay_Carnivorous_Plants]

This questing is regarding an ecommerce website that I hand wrote(html) in 1997.  One of the first click and buy websites, with cart/admin system that I also developed.

After all this time, the Old plain HTML look just doesnt cut it.  I just updated to XHTML w/ a very modern look, and believe the structured data will index better.  All products and current category pages will have the identical vrls taken from the old version.  I decided to go with the switch after manual penalty, which has since been removed... I figured now is the time to update.

My big question is that over the years, a lot of my backlinks came from products/news that are either no longer relevant or just not available.  The pages do exist, but can only be found from the Outbound Link Source.

For SEO purposes, I have thought a few things I can do but can't decide which one is the best choice.  Any Insight or suggestions would be Awesome!

1. Redirect the old link to the most relevant page in my current catalog.

2. Add my new header/footer to old page(this will add a navigation bar w/ brands/cats/etc)

3. Simply add a nice new image to the top of these pages linking home & update any broken/irrelevant links.  I was also considering adding just the very top 2 inches of my header(logo,search box, phone, address)

*note, some of these pages do receive some traffic.  Nothing huge, but consider the 50+ pages, it ads up.

[Chris.Menke]

I vote to 301 the crusty old links and be done with it. I don't think you'll be able to squeeze much more juice out of them in any other fashion so just set the 301s and move on.

[MoosaHemani]

301 the old pages to the new pages that are most relevant to the pages so that user experience should not get hurt!

**If links are spammy then try not to redirect (at least without disavowing bad quality links)

[Southbay_Carnivorous_Plants]

Yeah because of the age of my website, there was just news that was picked up YEARS ago... a lot are hi-pr links, i just want to make sure I do the right thing with em because as it stands right now any traffic gained from these now is 75%+ bounce rate.  Good anchor text for most, 301 is what I was thinking about first... then i thought, maybe just wrap the pages in my new header and hope the searches dont remove or derank these random pages.

Again - We are talking about 50 pages, which bring in about 4k clicks a month... Albeit not huge, just didnt know what to do with them.

One more Idea - I make a new different header that used a "nofollow" on all links for all my category & brand pages, then use it to wrap these old pages... The idea would be to preserve the "old content" , and hopefully keep the pages ranked #1 for their respective low volume searches...

Would that even work?