That sounds like a good trip. That bed and breakfast in Gallivare looks pretty good for the price, it was fully booked when we were there last year. Also you are a short walk to O'Leary's
which Mrs Meltwaterfalls and myself use as a shorthand for when there is a dearth of eating options.
I quite liked Lulea, it isn't stunning, but a very pleasant place to be. There was a great deli
on the waterfront, rather pricey but great food.
Arvidsjaur was pretty work-a-day, but again we had a lovely lunch there and the people were very friendly. The Lappstaden itself is pretty small. It was handy for us to call into as it was on our drive up from Skelleftea (also has a nice wooden Churchtown
) though I am not sure if it will reward a long drive as much, but could make a more interesting loop back to Lulea.