First of all, I urge you to try to find a second set. Maybe someone is selling one cheaply because the box is in poor condition. Twice as many Campaign Cards does improve the game. And try to get the second edition, it is much better than the first edition.
Rule Amendments to Mr President
All players throw two sets of dice. One set determines which states they may campaign in, and the second set is used for the non-campaigning functions.
The second pair of dice
Throw a double
Throwing a double forces the player to take a card from the Campaign Headquarters pack. He does this prior to, and in addition to, making his normal move.
Players may advertise instead of campaigning. To advertise he must commit himself to a minimum payment of $1,000,000 even if he decided not to use any of the drawn cards. Rejected cards are shuffled into the pack.
Player may elect to debate
Player may Fund Raise
Any other total
Ignore and campaign normally
The Campaign Headquarters Pack
Remove the 'Miss a turn' cards from this pack. It is ridiculous that a 'missed plane' should hold up your election campaign spread over several months.
Final part of the game
At present the optional debating rule unbalances the game. To acknowledge the impact of TV, a player may, at the end of the game, take one additional card more than his opponent for each debate he has won (remember that each challenger derives considerable benefit in the actual debating procedure in the game). These cards must be distributed by him as equally as possible around the country. In fact, the distribution of Undecided Voter Cards for both parties should be dealt with randomly. That is to say, under the rules you can place them where you wish, but in fact this means, for example, that you could post five cards for California although you never went there during the campaign. It thus makes a mockery of all the campaigning that went on before. So, therefore, I suggest that both parties shuffle their Undecided Voter Cards and post them as equally as possible but without knowing which card is going where.
In the final part of the game players should not be prevented from making use of Press Endorsements etc., simply because their opponents do not have the cards with which to replenish the Undecided Voter Stack. A player without such cards gives a card from his hand.
Using two packs of cards
If you can afford a second set, merge the Campaign Cards into one deck. This enables you to agree upon a finishing time. Once players have run out of cards their campaigning is over but their opponents can continue up until the finishing time.
If both players are left with cards in their hands when the time is up, these are totalled and the party with the excess cards adds the excess number to the Floating Voter Pack.
If one player has none, all in the opponent's hand are put into the stack.
These sound like excellent adjustments to a game that is actually quite good once one uses a few 'house rules'.
Hopefully, I'll get a chance to try out your rule amendments soon.
Back in '04 when I ran an adaptation of Mr. President for the 2004 election at the WBC, I bought enough copies on e-bay to have plenty of card decks. Copies generally sold for $5 - $10. I found the 1971 edition to be significantly different, however, compared to the 1967 version (which my brother and I have always played). When bidding on e-bay I found that by viewing photos of the actual game being sold and comparing the image to my own game I was able to buy only the version I wanted. So, I wouldn't bid on copies that weren't visible. IIRC, I think the front of the rulebook was the clincher when determining which version was on offer.