Staying classic is definitely the way to go. Doing something that has a lot of color might turn some people away. I think choosing an off-white/light cream for the whole house with a moss green trim would be fun, cute and kind of eclectic without being too much.

similar to the link below.

or even this!

That's a lovely color palette, and it would definitely fit the neighborhood. I was worried that something too light would too quickly be stained from the copious leaf fall, but after a few months, that will be someone else's problem. ;-)

I agree with Borth-Wilson, go light since the cottage, which is charming BTW, is nestled in the trees and shrubs. A light shade of yellow and white trim will make it look like the sun is shining on it. A small covered porch would really set off the entrance. You may not be able to remove greenery, which I don't think you need to, it is after all a cottage, but a good trimming would tidy things directly around the structure.

Cream, ivory or light yellow with green or gray trim, white accents. Prune any shrubs that are directly in front of the windows so they reach at most one foot below the window sills and one foot away from the house walls. This house structure and setting are already attractive. Remove any CFL bulbs inside and in lamp posts and replace with incandescent bulbs right before it goes up for sale. If you can afford new LED bulbs, some are quite good. Add bright new door mat. If you can afford to put planting mix as a mulch under all the shrubs, it gives a very good impression. Shredded bark is good, too.

I LOVE both of the previous suggestions, but wanted to throw one more color out there. A popular outdoor color we use often is a light beige/gray. These colors seem to mix both cool and warm tones. Combined with white trim...it is gorgeous and appeals to many homeowners. The home shown in the picture is painted with "Perfect Greige" by Sherwin Williams. It also looks great against greenery and you can add a pop of color to the front door, which adds additional charm.

actually, since I think the house is small, i would paint it something that will make it pop - i'd go with dark red with snappy white accents, and put dark bronze hardware on the outside with a cute lamp on the porch.

I am so sorry for your loss, and hope that this process feels a little like finishing something she was proud of. Very difficult financially to be left with a project but paint and siding can save you. If you were going to live in it, red or blue with white would be darling. For sale, I think they are right that an off-white / creamy white tone is the best and I think the vegetation gives it privacy.

Bm collingwood is a proven tone - you can look for hardieboard in this type of tone - http://www.benjaminmoore.com/en-us/paint-color/collingwood

Let me point out that you should not have contrasting trim at the corners of the house - that should match the siding - only trim that wants to contrast is your eave, fascia, door and window trim. I would also suggest you pull down the carport. It doesn't relate to the cottage architecture, comes into the house below the door header height making the front entry feel odd and highlights that there is no garage/ takes up a bunch of the front. Better to pull it down than have it as is. It is the wrong height as it doesn't relate to the height of the house. Pad that area with gravel and then decomposed granite on top. Stage it with patio furniture when you go to sell. Taking it down will increase the perceived value of the home.

If you can paint the sashes of the windows (as it appears that you can) paint them the slightly contrasting front door color to tie it all together. If not, they will be great in white. You could also use white trim instead of the mid-tone at all the windows and doors, but use the contrast for the eave and foundation.

Here, with a soft neutral off-white like collingwood, the front door would be lovely as "pining for you" http://www.benjaminmoore.com/en-us/paint-color/piningforyou#ce_s=pining for you
and the trim in a mid-tone in the same family bm hampshire gray http://www.benjaminmoore.com/en-us/paint-color/hampshiregray