6 weeks and an hours riding is not bad for an "OldUn" Listen to you body is good advice so remember that if you are on an out and back ride- Turn back well before you feel it. Pointless talking about getting speed unless that is your aim- it will come naturally. Just gradually increase distance and get the body- legs and lungs attuned to riding. You haven't mentioned Butt Pain yet so it is either not a problem or it has not bothered you yet. That will ease with more time on the saddle.

Before adding Hills- get used to the bike and gears. Hills will come easy but just gradually up the length or severity of the hills as you progress. One thing most newcomers will have trouble with is Cadence. That is pedal speed on the legs (RPM) most start slow and think they are being efficient. it is not. Up the speed of the legs to 70 or above and you will find hills easier and you take pressure off the the knees. check by counting how many times the legs turn a full revolution in 15 seconds and mutiply x 4. 70 and above will be ideal-eventually so work up to that. the aim is whatever you want it to be but most here try to get above 80. Fit Bu**ers will be above 90.

As it is you are getting out on the bike and enjoying it. Perhaps time to work on distance- speed will come- and ride as often as you want. It will be good to put some effort in on the ride so you can improve but do it gently. Slight up hill near the end of the ride and instead of turning the pedals- Go for it. 200 yards at a time is enough. That will help on speed- strength of legs and Heart rate.

As it is you are doing fine. Except for the Pie bit. you haven't mentioned it yet so I assume you are not taking any on the rides. set a goal. 20 mile ride with a cafe after 10 to 12 miles. Stop for a coffee and Pie. when you can do that- you are into cycling.