Still perched high on the bestseller lists after more than 26 weeks in the top spot, Virginia Evans’ “The Correspondent” surely ranks as one of the most successful epistolary novels of all time. Now that Lionsgate has won a seven-studio bidding war to turn it into a film starring none other than Jane Fonda, one has to wonder how designated adapter Cat Vasko will handle all those letters and diary entries to make the film as compelling to viewers as it obviously has been to readers.