Excellent maps Heber, it's remarkable how the inferred migration/trade routes match up for Bell Beaker and the much later Phoenicians. For that matter you can imagine the various shoreline promontories, bays, islands, river mouths and other coastal features would attract attention from seafarers of any time period, the pattern repeating itself over time in all ages.
I live in British Columbia Canada and think about the "pre-neolithic" style coastal communities that were here until just 200 years ago. There was a very dense population here, probably conservatively hundreds of thousands of people all along the coast and interior waterways. The coastline was dotted by thousands of inhabited sites, with some villages supporting up to several thousand individuals. Boat travel and trade were very extensive. Have a look at this map for reference to what I'm about to mention:http://www.bcarchives.gov.bc.ca/exhibits/timemach/galler07/images/abbcmapm.jpg
I worked with a group of Tahltan in northern B.C. who have tribal memories of coastal Haida or Nisga'a travelling up to a thousand kilometres all along the coast and far upriver specifically to indulge in a bit of raiding and warfare against them. So, in what is almost living memory we have records of high populations, long distance sea travel, and extensive trade networks all in a pre-agricultural (pre-neolithic) society of hunter-gatherers.
From the lens of my experience it strains belief that somehow there is a static, unmixed population of uniform paleolithic survivalists all across europe prior to the neolithic, which only the advent of agriculture begins to alter. This in my mind is the fallacy of "no mtDNA H and no y-DNA R1b before the neolithic" line of argument. Do people think offshore fishing, whaling, trade and tribal raiding (e.g. for women) originated with agriculture? People and goods would have been highly mobile, especially by water, and communities all along the mediterranean and atlantic facade and up the major rivers can be expected over time to pick up genes from distant populations. When have people not been fond of exchanging genes, after all there are 7 billion of us.