Maura, it is a very interesting discussion and you are right you have to some technical details of your equipment and photography method
Bokeh, you wont to have a nice bokeh. Bokeh came from Japanese word "boke", which means out of focus or blurred. Boke is just dependent on construction of your lens. Nothing to do with exposure time or aperture. Bokeh is depend on a figure of multi-disc, your aperture is made. Usually lens aperture has 6 or 8th multi-discs. In this case the bokeh looks like hexagon. More enhanced lens have 9 multi-disc. In this case the bokeh looks like a circle.It's all. Unfortunately your lens have 7 multi-discs. So you can't expect to get a best bokeh. Sorry.
Your lens can focus only down to 450 mm, also 2 feets, no closer to the motive you wont to photograph.
ISO. In the analog time, the low ISO sensitivity was very important, because of grain size of the film. ISO 64 was a very good and common to get pictures with out any visible grain. In the digital camera time, it looks total different. On the market, there is almost no camera which can accept ISO 64. The lowest figure is 100. But there is no problem with grain or noisy. You can set up ISO sensivity up to 800 ISO and get very good pictures. The processor on your camera is determining the picture quality. Don't be worry to use high ISO. You can take pictures with out tripod and you are almost independet on wind. Set up time to 1/200 or 1/400 are let your camera adjust the aperture. Is your picture to dark increase ISO sensitivity. Try and error, it's the best way.
If you wont to use flash, switch your camera to manual. Aperture 5,6 time 1/200 and take a picture. Using flash, the back ground become dark, but e.g. flowers become sharp and well exposed.
I hope you can follow my poor English.