You are confusing positive and negative claims. 1) Vikings were definitely at point X. 2) Vikings did not get further than point X. Yes, due to the likelihoo

You are confusing positive and negative claims. 1) Vikings were definitely at point X. 2) Vikings did not get further than point X. Yes, due to the likelihood of undiscovered evidence, you can assume that things happened for which we don't have concrete evidence. You just can't determine exactly what those things are, so there isn't really anything interesting you can say about it. I don't think archaeologists ever make claims like "People X never reached Z" when Z is an easy 50KM journey from Y, where People X were known to have been, without pretty convincing evidence to the contrary (e.g. a mass grave containing the entire estimated population, showing they all died pretty much on arrival) Your claim that archaeologists don't think that way is bogus. How do you think they decide where to look for new evidence? A lot of archaeology may be driven by building works needing to prove they aren't going to destroy a Roman villa, but plenty is still driven by academics thinking that a particular meadow has a good chance of containing artefacts.