In regard to the assertion concerning the presence of Dacians as far as Jutland:
"T. Makiewicz published a series of publications devoted to
enigmatic features –floors of fired clay datable to the close of the Pre-Roman and the early Roman period. Commonly interpreted as the remains of sanctuaries, recorded in settlements of Przeworsk Culture, mostly in Kujawy, but also at Jaroslaw, as well as in a number of other sited in Poland,
these features have been identified also in the Jutland Peninsula. Their
origin were traced to the La Tene culture or alternatively more convincingly to the Thraco-Dacian cultures." (p.118)
The wording is a little confusing, but it seems to talk about a Dacian influence upon the architecture in the region. As you can see it does only speak of
features which could originate from Dacian culture, not necessarily the actual presence of Dacians there.
A very interesting opinion on a somewhat related topic show that “several of the Jutland settlements show
signs of Roman influence, for example paved roads, entrances and also ornamented clay tiles on fireplaces (…)." Old Norse Religion in Long-Term Perspectives, p.
208
At the same time, specialists from
Poznan Museum state that: “The
origins of these temples (in Sławsko Wielkie) are rooted in the
Hellenistic world. They appeared in the Kuiavia region during the second century BC - in a much diminished form -
via the Celtic cultural realm.”