"The unpainted house stood on the hill, seeming deserted."

"The cowboy walked down the street, trailing a roll of toilet paper."

The participle phrase at the end of each of the two sentences above is
nonrestrictive.  Nonrestrictive participle phrases are set off by commas.
Therefore, the two participle phrases are set off by commas.  But
something in me wants to strike those commas.  I gues my reasoning would
be that in these cases the participle phrases are set off by intervening
words and are therefore not in danger of seeming restrictive as they would
if they were right next to the nouns they modify.  (Whether they really
modify those nouns is another question; they seem so adverbial.)