I think a lot of her isolation has to do with the fact that she is her father's caregiver/companion and her father stays close to home. I don't think she is able to see Isabella in town. Who would take care of DOMW?

From chapter 3:

Mr. Woodhouse was fond of society in his own way. He liked very much to have his friends come and see him; and from various united causes, from his long residence at Hartfield, and his good nature, from his fortune, his house, and his daughter, he could command the visits of his own little circle, in a great measure as he liked. He had not much intercourse with any families beyond that circle; his horror of late hours and large dinner-parties made him unfit for any acquaintance, but such as would visit him on his own terms.