Many of the upgrades you are planning will have positive impact upon resale but if your plan is to sell 4-5 years, your return on investment will diminish. Replacing the roof will be important and the longer the life span the better. With the trend toward green building and living, the better the sustainability of anything you put in or on the house the better. Use materials and paints that are "earth friendly". As far as landscaping, use plants that are native to Oregon, those that do not require a lot of watering outside of what they receive during our rainy months.
You can get a lot of good information from www.earthadvantage.org. Click on Programs, Residential Remodel. They also offer some financial incentives to replacing old furnaces, water heaters, toilets, etc. Earth Advantage Institute is an Oregon based organization.
You can also find information on my web site (link below) under Seller Info, click on the Remodeling Return on Investment link to see what the ROI on different remodeling projects you might do in the house, the costs, etc.
I hope this helps. Good luck and please let me know if I can ever be of service to you with a real estate transaction.