Without weighing in on your overriding premise whether Charlotte's marriage will be satisfying long-term, I do note that once the Collinses inherit Longbourn, they will be closer to family and Meryton society and will also have a higher income for entertaining and travel. While Mr. Bennet may not have taken his family to London, there is no reason why Charlotte and Mr. Collins may not choose to go there, it being only a half-day journey and on the way should Collins need to check up on his curate in Husford. So we cannot assume Charlotte's social circle will always be what she now "enjoys" around Hunsford, whether that is merely business or has some pleasure for her.