What would be good route to follow for a RTW.
Basically using only land and sea transport.

Want to travel to every region and continent. If possible.

Whats good route to take with out back tracking. etc.

Any good suggestions?

Every region, hu? I'd say, that is at least a two years trip - probably a bit more. Especially with as little air travel as possible.

Here it goes (starting in Europe)

Start in Finland
To Greece
To Spain
To Morocco
Down the West Coast of Africa (tricky)
Up the East Coast of Africa to Egypt
Israel - Lebanon - Syria - Turkey
Up the left side of the Caspian Sea (Preferably Iran, Azerbaijan)
All the way to Vladivostok
China - Mongolia
To Central Asia
Pakistan - India - Nepal - Tibet
China
To South East Asia
Indonesia
Ferry your way to West Papua (including hoping over to the Philippines if you like)
PNG
Boat to Australia

So far all is easy. Now it gets tough avoiding flights. Generally, I'd say just fly to NZL and then on to Buenos Aires.

South America
To Central America
To North America

Done.

Looking at it, I'd say it'll actually take longer than two years to do it. It'd definitely be an epic trip. It has been done before. It's definitely possible. The question is, is this just a romantic idea of yours, or do you really want it. It's not going to be easy in some regions (Western Africa, around the Horn of Africa, Caucasus).