I had a solo vacation in Vietnam on April, 2018, for 2 weeks. May be it is a bit late to write about it but I traveled a lot meanwhile.
For Ha Noi area I used Adventure Indochina to plan my trip. Judy - my contact there - was more than helpful, admitting different changes in the programe I asked for. She is an asset for her company, took care that everything goes smoothly and in time. She also speaks a very good English.
I want to mention here the guides named Tai and Shrung (I do not know if I spell it correctly, sorry) and the driver Kai, who took care of me during 3 private trips. They were very competent, speak very good English, and offered a lot of information. Kai was an attentive and experienced driver.
I was very content with all of them and I would rate my time with them in Ha Noi as "excellent"
I truly recommend you this agency, if you want to have a memorable vacation in Ha Noi.