You need to be careful though, if you pick web services that complicates things, to do them properly [services] you need to understand stateless programming (WebApi/REST) is good for this.
Generally speaking, the more modern and shiny the end result, the longer it will take, as you will have to take in a lot of new concepts. Even with WPF you need to know MVVM and use Prism/Caliburn/MvvmLight
What about writing a simple winforms app that saves, retrieves and updates data to a database?
You run the risk of either
- Still trying to finish this after 6 months as you bit off more than you can chew
- Deciding .NET isn't for you due to the frustration and quitting
The question you are asking really is about how to be a decathlete, and attend several events all at once as you require several technical skills, C#, SQL administration, T-SQL, GUI skills, XML, installers and so on. The best advice I can give is to be patient, and don't give up, because once you master these skills, you can do pretty much anything