My Dad made this tree (pictures attached) and it uses a plug in light. I would like to convert it to an LED battery setup so I can put it in the middle of a table. I know how to solder but I have no idea how to make a circuit for LED lighting. I was thinking of buying a few 10mm ultra bright white LED's and hooking them up to some kind of battery that would fit in the base with an on off switch sticking out where the cord comes out. I have no idea what resistors I should use though and if the batteries would last long enough to make it worth it. I wouldn't mind going through 3-4 9v batteries per season (Thanksgiving to Christmas a couple hours a day maybe). But if the batteries would only last 1-2 hours, it probably isn't worth it.
Anyone have the know how to tell me what resistors would work and if it would last long enough to make it worth it? The
LED's I looked at look like they are approximately 3.4v to 3.8v each so I was thinking I could maybe hook two in series with some kind of resistor to a 9v battery? But I don't know if it would just drain the battery really fast or what. Or if two of them would be bright enough. I thought about 2 batteries and 4 LED's also. Not sure what other battery would be strong enough to power them but small enough to fit in the base. The base is only about 2-1/2" wide and 1-1/2" deep. I could get some AA or 9v in there. I don't think I could even fit 2 D batteries in it.

Any help would be appreciated. Thanks.
J_K_M_A_N