when packed for a long stay,and were also not particularly easy to carry any distance. Particularly not by a gentleman as anxious of his appearance/importance in the world as our Mr Elton ;-P

The butcher is helping Mr Elton by allowing him to use his cart to take the trunk from the vicarage to the " place where the coaches past".

Now, that might have been the Crown, but it is not specified in the text that it was.It could have been the nearest turnpike road or toll-house.

Indeed the descirption of the Crown in Chapter 24 makes me think it is not the main coaching inn for the area:

Their first pause was at the Crown Inn, an inconsiderable house, though the principal one of the sort, where a couple of pair of post-horses were kept, more for the convenience of the neighbourhood than from any run on the road

Wherever it was, it was sufficiently far away for Mr Elton, or his housekeeper, to ask for the butcher's assistance.