Please advise best travel option

Planning to visit Japan for 1 week in early Dec but not sure if we should visit Tokyo first or Izu Peninisula directly from Narita. Our plan is to spend 2 nights in Tokyo and 3 nights in one of the resorts along Izu Peninsula. Any recommendation for a reasonably priced resort with excellent views and beautiful parks, along with small shops for souvenirs?

That depends on your time of arrival in Narita. I recommend to calculate about five hours from arrival of your plane until arrival in Atami at the northern tip of the Izu Peninsula. An additional hour to reach Shimoda at the southern tip of the peninsula.

so, if your plane arrives anytime after 2pm, I would recommend to rather spend the first night in Tokyo than to travel to the Izu Peninsula directly.