Forget dinner, have some fun instead!
Rather than spending a few hours over dinner together in the evening, why not try to make a whole day of it filled with many fun date ideas. Make a plan of the whole day with activities that are indoor and outdoor, just in case the weather is against you and your schedule. For example, start in the morning with a visit to a gallery or museum and finish off the day with wine tasting at a vineyard. Try and squeeze as many activities into the day as your budget will allow, always remembering not to give away clues to what is happening next.