Hi Mark
Lived in Townsville for 10 years now.  Kelso is one of those suburbs that has a few socio-economic groups in it.  There is a fair bit of acreage, as well as some expensive properties near the river, but a big part of it is made up of cheaper housing.  It is also a fair way from anywhere (there is a primary school) but the new motorway has made it closer to the Uni and Hospital than it was.  Just be wary.

If you are looking for cheaper housing with good capital growth then I would suggest a suburb such as Deeragun/Mt Low.  There is huge infrastructure growth in the pipeline for that side of town.  Tried and true suburbs for rental properties include Kirwan, Riverside Gardens (Douglas), North Ward and Annandale.  More expensive to get into but excellent capital gains and high rental demand.  Oonoonba is also an up-and-coming area (older housing, but there is a new port access road to be built and property values are tipped to increase significantly).

Hope this helps.